A recurring story element is used as a form of tradition within a show each season. This doesn't necessarily mean it is a RecycledScript, as more often than not the only similarity is the subject. The story itself can go in many different directions. At other times it can just be a DayInTheLimelight, focusing on a specific character who normally doesn't get that much attention in the regular episodes. A sister trope to OnceAnEpisode.

It should be made very clear that this isn't about a specific MythArc that is scattered at different parts of the season. Usually this episode's schedule is very consistent, especially if it is set around {{Sweeps}}. In some cases fans may note that there might be a set-up for such a character to appear once a season, only for the consistency to jump around to multiple seasons between appearances.

Much of the time it ends up as a SomethingCompletelyDifferent episode.

Compare MandatoryLine, GoodTroiEpisode, OnceAnEpisode, MilestoneCelebration and any number of the holiday tropes such as ChristmasEpisode and HalloweenEpisode.
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!!Examples:

[[foldercontrol]]

[[folder: Anime & Manga ]]

* ''Franchise/{{Digimon}}'': Once a season you will have at least one main character with a sibling complex:
** ''[[Anime/DigimonAdventure Adventure]]'' has Yamato (as well as Taichi), ''[[Anime/DigimonAdventure02 02]]'' has Ken, Tamers has Jenrya, ''[[Anime/DigimonFrontier Frontier]]'' has Koji, ''[[Anime/DigimonSavers Savers]]'' has Tohma (and Masaru), and [[Anime/DigimonXrosWars Xros Wars]]'' has Nene.
** With one exception, a Leomon (or something in it's evolutionary line) will be a reccuring character and then die Once A Season.
* The ''Anime/{{Pokemon}}'' anime had Pikachu fry the bike of TokenGirl once per saga. ''In Best Wishes'', Pikachu shocked the TokenGirl herself.
** Ash and crossdressing also goes once per saga.
** With the exception of the Advanced Generation saga which had none and the Original series which had two, a projection of a Legendary Pokémon would appear to Ash and/or his friends at the beginning of that saga (Ho-Oh in Kanto, Suicune in Johto, Mesprit in Sinnoh, Zekrom in Unova).
** Ash always ends up losing the Pokémon tournament at the end of the series. He lost twice and won once in the Original Series, since it featured three different leagues.
** The first movie of each generation would feature the trio of fully evolved starter Pokémon, the exception to this rule being ''Anime/{{Pokemon 3}}'' in Johto and Hoenn's ''Anime/PokemonJirachiWishmaker''.
* ''PrettyCure'', for its first five seasons, had a number of traditions: infighting in episode 8, new mascot introduced just before the midseason powerup, new mascot runs away from home shortly after, just to name a few. Most of these were done away with along with the ArtShift and the name-based mascot [[VerbalTic sentence enders]] come ''FreshPrettyCure''.
* ''{{Slayers}}'' had one [[WholesomeCrossdresser crossdressing]] episode every season, and it was always episode 17. This was due to the first series' IdiosyncraticEpisodeNaming. Episode 17 was the "Q" episode (thus making [[StealthPun a "queer" implication]]), and the tradition stuck until Evolution-R. ''That'' season did something else for the "Q" episode.

[[/folder]]

[[folder: Film ]]

* Every Star Wars movie contained one BigNo. Obi-Wan in I and II, Vader in III, and Luke in IV, V, and VI. And someone must have noticed the disparity and pointed it out, because George Lucas is editing in another one from Vader in VI.
** Not to mention "I have a bad feeling about this," which has made its way into the ExpandedUniverse as well.

[[/folder]]

[[folder: Literature ]]

* ''Literature/KillTimeOrDieTrying'', set in a university, starts off each academic year with someone asking "Who failed what, and how bad?"

[[/folder]]

[[folder: Live Action TV ]]

* Supernatural: Every season finale begins with an extensive recap set to Kansas' "Carry On My Wayward Son", the show's unofficial theme song. There's also at least one episode featuring pagan gods per season (though there were two in season 5), and, from season 4 onward, one time travel episode per season.
* ''Series/HappyEndings'': Every season ends with a wedding. The pilot opens with a wedding as well, but it [[RunawayBride doesn't go so well.]]
* ''BoardwalkEmpire'': Once every season thus far [[spoiler: Nucky Thompson has narrowly escaped an assassination attempt.]]
* ''{{Series/Bonanza}}'': Starting with Season 12, a crooked businessman named Bradley Meredith (Lorene Greene in a dual role) came to Virginia City to cause trouble, most notably for the Cartwrights and his prime target, Ben. The first installment came in 1971's "A Deck of Aces." The second installment in what was to be an annual storyline, "One Ace Too Many," aired in the spring of 1972. A third installment involving Meredith's latest scheme to cash in on the Cartwright's name, was planned for the spring of 1973, but "Bonanza' was canceled before the script was completed.
* ''TheBradyBunch'': Starting with Season 3, the Bradys went on vacation to some far-out destination. The 1971-1972 season opener was set at Grand Canyon, while the summer of 1972 saw the family to to Hawaii (and was eventually aired as the fourth-season opener). In the fall of 1973, during the fifth and final year, the Bradys went to King's Amusement Park in Cincinnati, Ohio. And yes, Alice came along for each of these trips.
* ''TheApprentice'': The UK edition will feature:
** A catering task
** A task where the teams have to buy a list of items at the lowest price possible
** A task to create an advert
** A round of interviews. In recent episodes, these take place in the final, not the semi-final
** At least one candidate gets fired "with regret"
** Unless a candidate quits the show of their own accord or has to leave for some other reason, at least one episode will feature a 'surprise' second firing.
* ''Series/BuffyTheVampireSlayer'' had "Buffy's Birthday" episodes, where something always crashed her party. In the third season it seemed like Spike and Ethan Rayne were going to make yearly visits, but Spike [[PromotionToOpeningTitles became a cast member]] and Ethan wasn't seen after Season 4.
** Spike [[LampshadeHanging lampshades]] how something terrible happens on Buffy's birthday in the season six episode.
** Oh, yeah, and every season has a [[TheWorldIsAlwaysDoomed minimum of one attempt to destroy the world]]. This would often be the SeasonFinale, but sometimes it would come in the middle of the season, in which case it was rarely taken that seriously.
** The producers also commented that they worked hard to give Giles one line per season that sounds absolutely crazy out of context, and to lampshade its craziness. Their personal favorite was from Season 3's episode "Gingerbread":
--->'''Giles''': We need to save Buffy from Hansel and Gretel!
--->'''Cordelia''': Now, let's be clear, the brain damage happened before I hit you.
** Amy Madison made an appearance in human form once per season, except for season 5 (when she was absent) and season 6 (where she made brief appearances over three episodes).
** There were also the Halloween episodes (which, incidentally, all occurred in even-numbered seasons), where someone always claims that it's the one night the supernatural takes off. . . and yet some aspect of the supernatural didn't get the memo.
** After [[Series/{{Angel}} his departure]], Angel would show up for precisely two episodes a season in all but season 6.
* In every season finale of ''Series/{{Charmed}}'', the last shot is the front door of the Halliwell Manor closing, either being magically closed by Prue (seasons 1 and 2), another supernatural being (seasons 3 and 4), Chris (season 5), itself (season 7) or [[spoiler:Piper's granddaughter]] (season 8). The only exception is season 6, the final shot shows the doors of a hospital room closing.
** Though in the season 6 finale, Chris does magically close the front door. Only this time it happens during the episode (when he throws Darryl out) , and not at the very end.
* ''{{Cheers}}'' had the yearly "Bar Wars" episodes, in which Cheers and another local bar (Gary's Old Towne Tavern) competed to top each other in practical jokes.
* ''Series/{{Community}}'' so far has had a Halloween and Christmas episode in all three seasons.
** Also paintball, albeit the third season only had paintball in a brief flashback.
** Beginning with the second season, there's an annual episode that's done in the style of a documentary filmed by Abed.
* ''Series/DoctorWho'' has its yearly Christmas episode since te revival.
** The revival has to have a Dalek appearance every year (two in the first series), as mandated by the contract that allowed them to use the Daleks. Hence their flashback appearance in "The Waters of Mars".
** It hasn't been stated as a deliberate tradition, but every year of New Who has had one episode when they go back in time and meet a famous British person and often use the story to fill in a mystery in said famous person's life as a kind of HistoricalInJoke:
*** Season 1: Creator/CharlesDickens. Dickens planned to change the end of ''Literature/TheMysteryOfEdwinDrood'' to include the monsters he saw, but died before he could finish.
*** Season 2: QueenVictoria. They explained the mystery of her hemophilia to being attacked by (and possibly ''being'') a werewolf.
*** Season 3: Creator/WilliamShakespeare. A trio of witches is responsible for his lost play ''Love's Labours Won'' (and they try to imply that Martha was Shakespeare's "Dark Lady.")
*** Season 4: Creator/AgathaChristie. Her infamous disappearance was due to her memory being blocked after being attacked by a Vespiform (and Donna Noble originally thought up MissMarple).
*** Season 5: UsefulNotes/WinstonChurchill. One of his weapons to help win the war was going to be his "Ironside" (really a Dalek). Another episode focused on Creator/VincentVanGogh. It turns out that 'Sunflowers' was inspired by Amy putting some sunflowers in Vincent's garden.
*** Season 6: Pirate Captain Henry Avery. ''His'' infamous disappearance was caused by his crew being serially abducted by an AI on an abandoned hospital spaceship, and he chooses to stick around and pilot the thing when he finds out staying in the ship is the only way to prolong the life of his terminally ill son.
*** Season 7: They've stopped the "British" part, but Queen Nefertiti. She disappeared from Egyptian record 14 years into her husband's reign and was never heard from again. This is because when she was helping the Doctor fight a guy on a dinosaur-filled spaceship, she meets a much more interesting man in John Riddell and runs off with him.
** Beginning with the second series of the revival, there would be an episode where the Doctor and/or his companion(s) would have limited appearances. These are referred to as "Doctor-lite" and "Companion-lite" episodes.
** In addition to the main companion who travels alongside the Doctor, every series has another character [[GuestStarPartyMember briefly travel]] with them for a few episodes. Series 1 had Adam and later Captain Jack Harkness; Series 2 had Mickey Smith; Series 3 had Jack (again); Series 4 had previous series companion Martha and then nearly all previous companions in the finale; Series 5 had Rory Williams who became a full-time companion in Series 6; and Series 6 had River Song. Although Series 7 did not feature this, it did see see the transitioning of one full-time companion to another halfway.
* Several of the characters on ''{{Frasier}}'' make seasonal guest appearances, including his agent Bebe, his ex-wife Lilith, and their son Frederick.
** Like holiday episodes, the Seabees (Seattle Broadcast Awards) by definition came up only once a year.
* ''DoogieHowserMD'': Given that [[JustAKid Doogie’s young age]] is such an important factor in the series, his birthday (September 21) was always tied into the plot of every season premiere to pave the way into the next chapter of his life as a teenage doctor.
** Because Season 4 aired many episodes OutOfOrder, the initial “Doogie’s birthday” episode for the season was delayed until the next week (“Look Ma, No Pants”), in order to make room for the "VerySpecialEpisode” season premiere, which focused on the 1992 Los Angeles Riots.
** The “annual father-son fishing trip” episode theme was also repeated, each with a different twist, every season.
* ''TheDukesOfHazzard'': At different points of the season starting in Season 2, Hughie Hogg (Jeff Altman as Boss Hogg's even more crooked and unethical nephew) made annual appearances. Usually but not always, the plot involved Hogg coming up with a sure-fire scheme to make money for Boss, and Boss becoming wary but going along when Hughie said that he would also find a way to pass the blame onto the Duke boys; however, the scheme always had the ulterior motive of ruining Boss. It would be up to Bo and Luke to find enough evidence to run Hughie and his cronies out of town.
* After appearing several times during the first three seasons of ''{{Friends}}'', Janice still appears once each of the subsequent seasons.
** Every season, barring the second, has an annual ThanksgivingEpisode.
** Almost every season has an episode where Chandlers starts smoking again, though it never sticks, and sometimes only lasts for a quick gag.
* While not quite a seasonal basis, ''HogansHeroes'' frequently had something of an "evil twin" episode, in which, a doppelganger of a character would be introduced to the story, the Heroes use this to their advantage by kidnapping the doppelganger, having the original character masquerade as the doppelganger to thwart the latest Nazi war effort.
* ''Series/{{House}}'' would often towards the end the season (if not the SeasonFinale) have some sort of hallucination episode, sort of started by the "Three Stories" episode in the first season that had House using hypothetical situations to better understand a few medical dilemmas.
** House would also have one antagonist per season. Vogler, Tritter and Amber all play this role, as does Stacey's husband. [[spoiler:Amber occupies the position for two seasons in a row, in fact]].
** Several seasons also feature an InMediasRes episode near the end of the season (seasons 4's "House's Head", season 6's "Help Me" and season 7's "Moving On").
* ''LegendOfTheSeeker'' seems to be following the example of [[SwordOfTruth the novel series it's based on]], with a new Wizard's Rule each season.
* ''Series/{{Lost}}'':
** In every season premiere, the opening scene is a TomatoSurprise about the character being shown, the character's location, or both:
*** The series itself begins ''InMediasRes'' with Jack waking up in the jungle and discovering the plane wreckage
*** Desmond inside the nicely furnished hatch in season 2
*** Juliet and the Others living in a modern town on the island in season 3
*** Hurley being chased by police [[spoiler:in the future after being rescued]] in season 4
*** [[spoiler:Daniel Faraday]] with the DHARMA Initiative in 1977 in season 5
*** Jack meeting [[spoiler:Desmond]] on Flight 815 and the island being [[spoiler:underwater in the afterlife]] in season 6
** In every season finale, something pivotal to that season blows up:
*** The hatch door and the raft in season 1
*** The hatch (Swan station) itself in season 2
*** Many of the Others when they attack the beach in season 3
*** [[spoiler: The freighter]] in season 4
*** [[spoiler: The hydrogen bomb]] in season 5
*** [[spoiler: Parts of the entire fricking island]] in season 6, though that was more of an implosion
** Additional "once a years":
*** Since season 2, at least one episode each season is one long flashback (usually with a frame story). These are "The Other 48 Days" (season 2), "Flashes Before Your Eyes" (season 3), "Meet Kevin Johnson" (season 4), "316" and "The Life and Death of Jeremy Bentham" (season 5), and "Ab Aeterno", "Happily Ever After" (which flashes [[FlashSideways sideways]] instead of back) and "Across the Sea" (which ditches the frame story and features only one starring character, but played by a different actor) (season 6).
*** One member of the original cast has died each season. These are [[spoiler:Boone]] (season 1), [[spoiler:Shannon]] (season 2), [[spoiler:Charlie]] (season 3), [[spoiler:Michael]] (season 4), [[spoiler:Locke]] (season 5), and [[spoiler:Jack, Sun, Jin, Sayid (twice), the Man in Black [[note]]introduced in season 1 as "the Smoke Monster", became a main character in season 5, played by the same actor as Locke throughout season 5 and 6 outside of flashbacks[[/note]] and, technically, everyone]] (season 6).
*** Benjamin Linus gets the snot kicked out of him once each season he appears in. Characters who get the honors of beating his face in are Sayid (season 2), Jack (season 3), Sawyer (season 4), Desmond (season 5), Desmond again (season 6 [[spoiler: but in the sideways verse, and not out of malicious intent]]). Hilariously, [[spoiler:it at least partially provokes his "island awakening", which for most of the other characters is caused by reliving an emotionally meaningful event]].
* Before CerebusSyndrome plagued ''Series/{{MASH}}'' during its final seasons, in the beginning, the producers decided that once a season would have a DarkerAndEdgier episode; after a couple of seasons, they also decided to also have an episode or two a season that eliminated the laugh track altogether.
** As well, roughly once a season, there would be a "Letter to Home" episode, in which they would show brief snippets of life at the 4077th, with a FramingDevice of one of the main characters (usually Hawkeye in the earlier seasons) writing a letter to a loved one. (Although this has been played with several times. In one case, the FramingDevice was an official report Radar was filing, and in another it was a will that Hawkeye was writing while on a dangerous assignment. As well, another episode featured the entire cast writing letters to a class of schoolchildren.)
* ''Series/{{NCIS}}'': Tony gets framed for a homicide Once A Season. He is GenreSavvy enough to notice and lampshade it, but [[WrongGenreSavvy not enough to prevent it]].
** Gibbs builds and (somehow) disposes of a boat in his basement once a season.
** Since season 7, one fall episode will involve CGIS Agent Abigail Borin (Diane Neal).
* ''PowerRangers'' has only one instance where a SixthRanger doesn't show up in a season (season three, although that includes an entire ranger team stepping in for a StoryArc). They were so dedicated to the SixthRanger trope they created the American Titanium Ranger for ''Series/PowerRangersLightspeedRescue'' when the SuperSentai ''Go Go V'' original didn't have one.
** As well as the MidSeasonUpgrade, the ReunionShow (the traditional team-up began in season 7) and the [[SuperMode battlizer]] (began in season 6). The crossover specials didn't always happen (Ninja Storm and RPM, for complicated production reasons). ''SuperSentai'' always had a crossover movie though.
* During the latter half of SanfordAndSon, each season had an episode that featured a subplot involved Fred and Lamont's unorthodox method of filing their income taxes, while also exsaperating Marvin, their accountant.
* During the mid-2000s, SesameStreet had a story each season in which Zoe's pet rock, Rocco, turns up missing, because a wandering chicken finds it, mistakes it for an egg, and tries to hatch it.
* ''Series/TheSopranos'' tends to have one episode per season to showcase Tony's dream sequences.
** In every season, even seasons where his storyline is not particularly prominent everything will stop so we can focus on Christopher. Other characters receive episodes featuring them prominently but most of these episodes focus almost soley on Christopher's development or he is at least most central to the storyline.
*** Season 1: "The Legend of Tennessee Moltisanti"
*** Season 2:" D-Girl" and to a certain extent "Full Leather Jacket"
*** Season 3: Fortunate Son
*** Season 4: This one's the debatable but the season premiere and "The Strong Silent Type" are the prime candidates.
*** Season 5: "Long Term Parking"
*** Season 6 part 1: "The Ride"
*** Season 6 part 2: "Walk Like a Man"
* ''Series/StargateSG1'' has {{Clip Show}}s. Not quite every single season, but it seemed that way for a while.
* ''Series/StarTrekTheNextGeneration'' had yearly visits from Q (Apparently Gene Roddenberry wanted him to appear three or four times a season, but upon a lackluster second appearance they decided on a simple yearly visit). They also had the HolodeckMalfunction, which became a tradition for ''[[Series/StarTrekDeepSpaceNine Deep Space Nine]]'' and ''[[Series/StarTrekVoyager Voyager]]'' as well.
** Q notably didn't appear in season 5 (though he ''did'' appear, that same season, in an episode of ''Deep Space Nine'' for the first and only time), so season 6 made up for it by having him appear twice.
** ''TNG'' episodes about the [[TheWoobie painfully socially awkward and profoundly anxious]] Lt. Barclay almost qualify after his introduction in Season 3, but he didn't get one in Season 5 and instead, he got two Season 6 episodes. One of those two ("Ship in a Bottle") was also the Season 6 HolodeckMalfunction episode and featured some nice {{Continuity Nod}}s for both Season 2's HolodeckMalfunction episode ("Elementary, Dear Data", in which a [[SherlockHolmes Professor Moriarty]] hologram becomes self-aware) and Barclay (who was not on board the ''Enterprise'' during the events of Season 2, and whose introductory episode was about his holodeck addiction).
** ''[[Series/StarTrekDeepSpaceNine Deep Space Nine]]'''s producers allowed Colm "O'Brien" Meaney time off regularly to maintain his film career, so when they did have full access to him, they regularly put his character through the mill, either by having him serve thirty years for murder (albeit AllJustADream) or have his daughter disappear into a time rift or whatever (also because he was considered the likeable everyman of the cast, so [[TheWoobie making him suffer was thought to have more impact for the audience]]). The "O'Brien Must Suffer" episode became a tradition.
*** ''Deep Space Nine'' also did a mostly-comedic "Ferengi episode" about once or twice a season.
*** Several seasons of ''Deep Space Nine'' also had one visit to the MirrorUniverse which generally featured one of the Mirror Ferengi getting killed.
** ''Series/StarTrekEnterprise'' had at least one spotlight episode a season for the Andorian Captain Shran and his uneasy friendship with Captain Archer (although he did make a few minor appearances in other episodes). The fourth season, organized into mini-arcs of two-three episodes, had one with Shran in the middle of it.
* ''Series/ThirtyRock'' has Dennis Duffy, self-diagnosed sex addict, former beeper mogul and ex-Subway Hero, appear once a season.
** Also Devon Banks and Colleen Donaghy
* Some challenges or challenge types have been repeated in ''Series/{{Survivor}}'' they become a tradition. Examples include:
** The Car challenge held later in the game; averted by later seasons though.
*** The "Car curse". Whoever wins a car will not win the game.
** A survivor auction in place of a reward competition
** An EatThat type of challenge; but these appear to have stopped after ''China''.
** Family visits or a Letters From Home challenge
** The penultimate immunity challenge is sometimes a composite challenge consisting of obstacles from previous challenges in the game, or even past seasons.
** A challenge surrounding trivia about other Survivor contestants that season or opinions about other contestants.
** The Torch Walk or Rites of Passage as they are often called before the final immunity challenge, wherein the contestants still in the game (Final four or final three) remember the previously evicted players and then burn the torches down while sad music plays. They also have to go on a hike or boat ride full of SceneryPorn. At the end is always the final immunity challenge.
** The Final immunity Challenge is often an endurance competition. Often it is either physical endurance or willpower.
*** Subverted in a couple seasons. The final immunity challenge in ''Australian outback'' was the trivia (To be fair; this was the second season.) ''Gabon'' violated the tradition by having the final immunity challenge be stacking cards. ''Heroes vs. Villains'' violated this by having the final immunity challenge be a blind maze run to grab immunity. ''Redemption Island'' violated this by having the final immunity challenge be a large maze followed by the fourth puzzle in a row for [[CreatorsPet Rob's sake]].
** The final two or three being given a special breakfast on the last day.
** The final two or three burning down the camp on the last day.
* In the American ''BigBrother'':
** The first head of household competition is almost always endurance or physical competition of some kind. Averted in season 10 where the public voted on the first Head of Household.
*** The Houseguests voted on the first HOH in season 10, not the public.
** Majority Rules is commonly played within the first one or two weeks; explainable because the competition works best when there are about ten people.
** The head of household always receives a letter from home.
** Sometimes; a movie is shown to winners of a luxury competition.
** A shuffleboard type challenge is often played at one point.
** Sometimes, an arcade-like challenge is played.
** A challenge involving copious amounts of liquid or food is often played at one point.
** A food/Luxury competition is often ignored whenever the challenge is either an Endurance or a long-task.
** A veto competition where Otev (Or a previously evicted houseguest) asks houseguests to pick up an object with the answer to their question and bring it to them.
** A luxury or shopping spree challenge.
** Double Eliminations
** A "Before or after" competition.
*** A "True or false" competition similar to that.
** A visit from someone outside the house.
** Face morphing challenges
** The final three Head of Household competition is always played in three parts. The first part is always endurance, the second part is always a puzzle involving the order of houseguests' eliminations or the head of households, the third part is always asking questions about what the jurors would say.
* ''[[Series/RuPaulsDragRace RuPaul's Drag Race]]'' has a couple of challenges that crop up at the same time in every season
** The first main challenge will always be to make runway looks from unconventional materials
** Since Season 2, the main challenge for the fifth episode is always The Snatch Game
** The final five challenge is for the contestants to pair up with strangers and make them over into drag queens
** The final four challenge requires three different runway looks to be made and for the contestants to perform a show-tune together
** The final three challenge revolves around filming the music video for whatever new song RuPaul is promoting that season
* ''[[Series/TwentyFour 24]]'': Around episode eight, the Big Nasty Thing That's Going On turns out to be a small portion of the BigBad's overarching plan.
** And around episode 14, that BigBad is stopped and revealed in a side plot to be actually either TheDragon of the BiggerBad / EvilOverlord, or a free or ancillary agent whose operation was actually ''damaging'' the EvilOverlord's one.
** On a more ''meta'' level, since as early as Season 1, ''24'' has managed to predict an important item (usually a failure) of US foreign politics or military operations that actually takes place next year or a couple of years later '''in real life''': the first African-American President in Season 1 (way before its time); the US government [[AcceptableTargets blaming terrorist attacks on Middle-East countries]] to start a war for oil in Season 2; tortured or neglected agents defecting to the other side in Season 3; excessive demonization of arabs in the public media in Season 4; the US getting involved in the (mis)relationship between "mother Russia" and her annexed territories Season 5 (not to count revealing the President as the evil behind actually trying to start a war). Seasons 7 and 8 being the most recent ones it is not clear yet what ''24'' is going to end having predicted but it may be related to Sarah Palin as the first female President or American firms testing bioweapons in African countries (S7), or [[spoiler:the permanent damage that former Presidents have over the Office]] (S8).
** In almost every season, [[AnyoneCanDie someone important]] dies at 02:00 AM, or during the episode running that hour:
*** Season 1: former CTU District Manager [[TakeUpMySword Richard Walsh hands evidence to Jack and dies]] right before the hour (setting part of the tone of the series).
*** Season 2: Jonathan Wallace (the villain who carried the Cyprus Audio). Also, Jack "dies" at the end of the hour.
*** Season 3: Nina Myers dies at the end of the hour, [[ItsPersonal at the hands of Jack]].
*** Season 4: [[DeathOfTheHypotenuse Paul Raines]].
*** Season 6: Milo Pressman, feigning being the director of CTU to protect its personnel from a raid, dies during the hour.
*** Season 7: [[HeelFaceRevolvingDoor Tony Almeida]] kills Larry Moss shortly before the hour.
*** Season 8: Marcos Al-Zacar is remotely detonated near the end of the hour.
** Beginning with the second season this actually counts for the 7:00 A.M. hour as well.
* ''Series/TheOC'' had the annual Christmukkah episode.
* ''Series/Grey's Anatomy'' has had one episode every season where there is a case involving a penis. This is aslo true for cases involving someone swallowing something
* ''Series/{{Scrubs}}'' has the episodes where the narration shifted to another character, titled, in each instance, either "His Story" or "Her Story," or, on one occassion where minor characters were used, "Their Story."
** There was also usually at least one episode with the characters singing a song in one of J.D.'s {{Imagine Spot}}s (the show often had elaborate musical montages and characters singing in-character, but this was more like a full broadway musical). This culminated into a full MusicalEpisode where a patient with a brain tumor could only hear them singing.
* ''GossipGirl'' has thus far had at least one wedding each season.
** The last scenes of the season finales always take place a week after the prior events in the episode.
** Episodes seven and eight of the season always have significant events for Chuck and Blair.
* ''{{Titus}}'' started a tradition of having someone else [[ADayInTheLimelight narrate from the neutral space]], with Papa Titus taking it for an episode in season two and Erin taking an episode in season three. If they had more seasons they would have continued with Dave and Tommy.
* ''TheBigBangTheory'' has at least one episode a season where the guys dress up in costumes, sometimes coordinated costumes as well (and no, it's not always a HalloweenEpisode). It's enough of a tradition that an image of the guys is usually a centerpiece on the DVD inserts. The most epic one has to be where they all dress up (including Penny and her current boyfriend Zach) as the JusticeLeagueOfAmerica for a New Years party. Season six threw off the curve by having three, one at Halloween with no real theme, one with the guys as ''StarTrekTheNextGeneration'' characters going to comic con and, surprisingly, one with the girls getting DisneyPrincess makeovers.
** There is also so far one episode a season that includes Penny and/or Sheldon singing "Soft Kitty," a song his mom would sing for him when he was sick as [[ManChild a child]]. In the fifth season his Mom sang it to him herself.
** Starting in the third season there is at least one appearance by Creator/WilWheaton and Sheldon's rivalry with him.
** Early in the first season Sheldon's mom Mary came to visit, and mid second season Leonard's mom Beverly did the same. While it has sometimes been sporadic (Mary didn't show up in the second season and Beverly in the fourth) both have made fairly regular appearances.
* ''Series/RedDwarf'' has some form of time travel once every season. Since season 3, The Simulants, vicious human-hating cyborgs, would also turn up in every season, save the 8th.
* The Coaches' Challenge in ''Series/TheUltimateFighter'', in which the opposing coaches go head-to-head for $10,000 by playing a different game each season, such as bowling or table hockey. The only season this didn't happen was Season 4 "The Comeback," which did not have team coaches.
* With the exception of Season 4, ''Series/BreakingBad'''s Wendy has played a small but crucial role once every season.
* ''Two Pints of Lager and a Packet of Crisps'' features the "f-word" only once in each series, always in the series finale.
* In every season of ''Series/InsomniacWithDaveAttell'', Dave would visit NewYorkCity for the season finale, and end with returning to his apartment.
* ''WheelOfFortune'' has certain theme weeks that it does every season, such as Big Money Week, Going Green Week, a college week, a Best Friends week, etc.
* ''{{Roseanne}}'' had an annual Halloween episode, which would often parody the tropes of the annual Christmas episodes that were common in other sitcoms of the time.
* ''{{Series/Merlin}}'' has at least one tournament. Someone usually tries to sabotage it to kill Arthur or in the past, Uther.
** Merlin actually gets credit for something.
* ''{{Monk}}'s'' second season introduced his annoying neighbor Kevin Dorfman, who would pop up once season afterwards to help Monk out. He notably didn't make an appearance in season 6, so in season 7 he showed up twice: Once in a brief cameo during the 100th episode, and again properly near the end of the season [[spoiler: where he then wound up being the [[BackForTheDead murder victim]] of the episode.]]
* From the second season onwards, ''{{Series/The Mentalist}}'' has at least one episode per go focusing on the Visualize Cult, twice coinciding with the MythArc.
** Also, four out of five seasons have Jane coming back to the CBI after having quit or losing his job for whatever (often the same) reason.
* Each season of ''{{Series/The Bob Newhart Show}}'' had a ChristmasEpisode. While it may not seem like a big deal now, back then it was rare for TV shows to have more than one Christmas episode.
* The first three season premieres of ''Series/{{Revenge}}'' have opened with a flash-forward to midseason. They've also all featured the Graysons' Memorial Day charity auction that kicks off the summer in the Hamptons.
* In ''EverybodyLovesRaymond'', the recurring joke about the only meal Debra Barone could cook with competence - lemon chicken - was the Once A Series event. For instance, in a flashback to their courtship, it was the first dinner she cooked for Ray; at the time he expressed a wish to eat it every night.

[[/folder]]

[[folder: Newspaper Comics ]]

* The newspaper comic ''{{Curtis}}'' is renowned for its bizarre and [[BigLippedAlligatorMoment over-the-top]] Kwanzaa stories, which are often the most entertaining comics he does. (There seemed to be none in 2013, though, as the boys dealt with a crazy babysitter while their parents went to a holiday party.)
* ''{{Garfield}}'' always had birthday strips, mostly about how much Garfield dreads them.
* Several recurring jokes on ''{{Peanuts}}'' occured once a year. These included Lucy pulling away the football when Charlie Brown tries to kick it, Linus awaiting the Great Pumpkin, and Schroder celebrating Beethoven's birthday. There were also strips commemorating D-Day, and Snoopy going to drink root beers with Bill Maudlin every Memorial Day (based on Charles Schultz's real-life ritual with Maudlin, a cartoonist famous for his satirical cartoons on military life during WWII).
* About once a year, BeetleBailey does the gag where the officers receives a written order from the general, with one obvious spelling error that changes the meaning completely. It always end with the officers following out the order exactly the way it was written, because they'd rather look like idiots than to tell [[BadBoss the general]] that he did a mistake.

[[/folder]]

[[folder: Web Comics ]]

* In the webcomic ''Webcomic/OzyAndMillie'', there is a story arc that occurs once a year in which Ozy somehow loses all his fur. This is explained to be because of a family curse that only effects Ozy because he's the only member in the family to actually have fur. It is later explained that the whole curse story was a lie told to him by his father. ItMakesSenseInContext.
* ''SomethingPositive'' tends to start each year off with an "Old Familiar Faces" arc, featuring the activities of the characters that have dropped OutOfFocus.

[[/folder]]

[[folder: Web Video ]]

* ''WebVideo/TheOtherSide'' has a number of annual traditions:
** The sixth episode of every season sees the episode's spotlight character stabbed to death, right before they get a flashback.
** The penultimate episode of every season has Virginia kiss a man. In Season 1, it's her nemesis Turk (she's in disguise) and in Season 2 it's Hawaii.
** The final episode of every season has Arizona show up (for the only time each season), wreak havoc, and then leave.

[[/folder]]

[[folder: Western Animation ]]

* On ''WesternAnimation/CodenameKidsNextDoor'' there is a CAKED episode every season.
** Also, each season had an [[BizarroEpisode "art episode"]]. Season 5 didn't have one, but the following season had two.
* ''WesternAnimation/TheSimpsons''
** Their annual Treehouse of Horror episodes, starting season 2.
** Sideshow Bob comes to commit some crime.
** They use to have more in the early seasons, such as an Itchy & Scratchy-centered episode, a Santa's Little Helper-centered episode, etc.
* ''WesternAnimation/AmericanDad!'' has a non-canonical Christmas episode every season, as well as non-canonical episodes parodying a film or tv show. Most episodes have the main story focus on Stan or Roger, but there are always a few per season that focus on Steve or Francine as well.
* Each season of ''WesternAnimation/TeenTitans'' had one episode where things would go even zanier than normal. While most episodes had a somewhat serious plotline with a strong focus on characterization, these episodes would just toss all that aside and throw in as much surreal, nonsensical humor as they could.
** Season 4 had two of these types of episodes.
** Notably, these episodes usually show up before two or three part season finales, acting as a breather episode before things got ''REALLY'' dark.
* One person dies per season in ''WesternAnimation/AvatarTheLastAirbender''. [[spoiler:From season one to season three, in order, that's: [[HotbloodedSideburns Commander Zhao]], [[WellIntentionedExtremist Jet]][[note]]Though it was often debated if he was actually killed before WordOfGod confirms it.[[/note]], and [[TheSpeechless Combustion Man]].]]
* After its second revival (its 4th season), ''WesternAnimation/FamilyGuy'' started to do this with the [[OverlyLongGag overly long non sequitur]] of Peter fighting the giant chicken from the [[MillenniumBug [=Y2K=]]] episode in season 1. After 3 or 4 seasons this was stopped.
* ''StarWarsTheCloneWars'': Ahsoka Tano had one DesignatedGirlFight in each season: [[spoiler:with Asajj Ventress in Season 1, a Mind Raped Barriss Offee in Season 2, Aurra Sing in Season 3, Bo-Katan in Season 4, and again with ([[FaceHeelTurn a now genuinely evil)]] Barriss in Season 5.]]
** [[BountyHunter Cad Bane]] also showed up for one story arc each season through Season 4.
* ''WesternAnimation/MyLittlePonyFriendshipIsMagic'': The Elements of Harmony are used Once A Season. Twice in season 2.
** [[spoiler: Seemingly abandoned after the Elements were returned to their rightful place in the Season 4 premiere.]]
** About once a season, [[Recap/MyLittlePonyFriendshipIsMagicS1E25PartyOfOne one]] [[Recap/MyLittlePonyFriendshipIsMagicS2E3LessonZero of the]] characters has a complete SanitySlippage episode, with exception to the short season 3 ([[Recap/MyLittlePonyFriendshipIsMagicS3E6SleeplessInPonyville though it comes close]]).
* ''WesternAnimation/SouthPark'' has been [[TheyKilledKennyAgain killing Kenny]] Once a Season from Season 7 onward, as opposed to during the first five seasons where the practice was inverted by killing him OnceAnEpisode and instead had it so that he survived one episode every season. They've also had at least one episode focusing on [[EnsembleDarkhorse Jimmy]] [[CreatorsPet Valmer]] a season since his introduction in Season 5.
* On GarfieldAndFriends, there's a meta example. Garfield's friend Floyd the mouse appears in a episode Once A Season and complains about how he's only the show once a season.
* ''DuckDodgers'': Each season had one episode focusing on just Marvin the Martian and K-9 in a common everyday situation. Lampshaded by Dodgers in one of them.
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