2Gamerz has been experiencing this due to the creator having to balance college along with two comic strips at once.
Achewood has been falling into this for a while, with multiple days between each update and the author repeatedly pushing back his own deadlines. Eventually, he just put it on hiatus, with strips coming out once every several months. It's now somewhere between cancelled and on indefinite hiatus, with the author having announced he prefers to focus on his various other endeavors and may or may not eventually return to doing Achewood when he feels like it.
Adventures In Ninja Cookery (not to be confused with The Adventures of Dr. McNinja) never had an official schedule, but the author said he would try for once a week. Updates have taken as long as fifty days to be released.
Alice was last updated on July 7th 2006. There has been talk about perhaps restarting it, but it's not looking good since the update of a revival was in June 2009. It did eventually resume updating, but stalled again on January 30th, 2013.
Alice And Kev, the Sims 3 Reality Webcomic Thing, was updated regularly until the proprietor admitted a Creator Breakdown and abolished his schedule... at which time, posts ceased entirely. After about a month or two, he continued updating up to the blog and concluded its story.
Alpha Luna: lycanthrope drama, old-school monochrome linework, full-page format, weekly updates... with unscheduled pauses that can last half a year or more.
When And Shine Heaven Now was being produced (it's now complete), most schedule slips that happened were due to the host site glitching up or going down. When Erin did need to take a break (usually due to schoolwork, illness, or busted computer), she filled the spot with guest comics or features on websites and, toward the end, Integra sightings. Only once did she deliberately delay a storyline. She didn't feel comfortable posting a story about a fictional burning London around the time the real London was burning due to riots.
Angels2200 has gone through periods of dormancy over the years; the most recent one started in July 2011 after an announcement of family health issues (which as of December 2014 remains the last non-strip communication of any sort from the artist.) One single strip was posted in December of the same year, then another in June of 2013, and then a longer spurt of activity in summer 2014 before silence fell once again.
Applegeeks Lite updates every Monday, Wednesday and Friday without fail (though it was only Wednesdays and Fridays at first, the first Monday comic being #49). The main Applegeeks, however, updates erratically at best - and has been reduced to only a single issue per week. As a result, despite AG Lite beginning in 2006, three years after the main comic, the thousandth overall comic was AG Lite 476 (Wednesday, June 24, 2009)—almost half of the overall output. In fairness, a black-and-white comic strip is considerably easier to make than a full-color, full-page comic. In late 2010, updates started to become sporadic at best until Haque finally put the comic on hiatus.
Painful in Avalon, where the strip, meant to run on a three-year schedule corresponding to school years, suffered numerous delays in the final year, forcing the author to backdate new strips, until giving up and writing a "strip" saying in text what happened between the most recent strip and graduation. And even that was lacking, especially compared to what was given to the readers before.
Axe Cop entered into a hiatus in the summer of 2012 when the production of the Axe Cop television show overtook the strip's production schedule. This also led to the author's other webcomic, Bearmageddon, going on hiatus as well (after its schedule had already led to some update delays and a drop of two pages a week to one.)
Blip had been going since the beginning of 2008, and only in spring 2011 fell behind due to a combination of computer ills and a probably much needed vacation for Sage. Comics still update daily, but the dates are off by about a month. By fall/winter 2011, months could pass between updates.
Matthew Taranto, creator of Brawl in the Family, lives in Louisiana, so he's had to take occasional breaks from updates in order to evacuate from hurricanes. A more prolonged slip happened when he got Crohn's disease.
Butternut Squash once had a fairly regular weekly update schedule. But since 2007, instances of guest comics, filler art, and seemingly-endless piles of excuses and pleas for patience courtesy of the creators have become the norm rather than the exception. This has led to some fairly tense exchanges between the creators and readers in the comments section under each sporadic-at-best "update."
Cat Nine for Take Two, the schedule has slipped from thrice a week to just once a week, sometimes he'll miss a week plus it updates on random days. Most of the time the delays are caused by stuff happening in life or school. Recently though it seems that he's going for updating once a week on Sundays.
Chopping Block has had several of these throughout its run, many of which last several months. At the end of one such hiatus, there was a short set of strips involving Satan looking for Butch (the star of the comic). Another schedule slip caused that to become an Aborted Arc. One example: February 21, 2008 to January 2nd, 2009 - eleven months.
Captain SNES: The Game Masta went for about a year in the middle of Act 3 without any substantial updates, except for a few filler strips, before resuming. Particularly frustrating since it has one of the most complex plots of any sprite comic around. Fortunately, 2011 was a completely different story...
Casey and Andy had several very long hiatuses during its run, although it has since wrapped up its plot and ended for good.
Chugworth Academy had multiple slips in its MWF update schedule before stopping to update for almost two years. A series reboot lasted three strips, never to be updated again to this day.
This happened to the creators of Claude & Monet several times for several reasons, the worst being a two-month hiatus due to their server being repeatedly hacked. After the artist burned out on a Tues/Thurs schedule, they've since moved to a Tues/Fri schedule with better results.
Metal Gear Solid fan comic The Cobra Days started out as a Monday/Wednesday/Friday comic with occasional misses, slipped to three or four comics a month... then one or two... August 2008 saw the posting of the fourth new comic of the year. It was officially cancelled in January 2011 after almost 11 months of sitting stagnant.
Collar 6 is generally good about avoiding this, even as its schedule increased from one a week to three and then five, though it still slips due to illness-related reasons. Its author, Wolf, is good about giving a heads-up in newsposts and the forums when this happens.
College Roomies from Hell!!! had a strong seven-day schedule for several years, then dropped off to five per week, then three, then weeks or even months could go by without a single update.
Cosmic Hero author Ace Sparks promised on his last update that he would keep on updating soon... that day was 20 November 2008.
Directions of Destiny ran three chapters, moved to Wirepop and started a reboot, then left Wirepop and stopped updating for two years before finally updating a few times in 2008. Occasional updates to the site indicate that the author wants to continue, but so far, in spite of occasional trickles of concept art, the author's personal life has completely eclipsed the comic.
Dragon Tails. The original run of 2000 comics never had a late one. Then the author ended it, then restarted it, and ever since the update schedule has become entirely random and unpredictable.
Dresden Codak was exceptionally bad at this for the longest time. The update schedule was completely random until author Aaron Diaz promised weekly updates as part of making the comic his full-time job... upon which the update schedule continued to be completely random. Following the announcement, the next comic took six weeks to arrive, and then the strip spent a while being updated about once every twenty days. Then Diaz was in an accident that left him unable to draw and broke his computer, erasing the sketches he had in progress and putting the series on temporary hiatus. Few noticed. For a long time it was pretty much a given that you'd have to wait several months or more for another comic. Then came Patreon, which Diaz uses to pay an assistant. As a result, starting in March 2015, the comic is on a fairly reliable schedule of one comic every fortnight. How long this will last is unknown.
Brian Clevinger generally did a solid job with 8-Bit Theater, but interruptions and delays popped up not infrequently. Hurricanes would hinder the Sprite Comic a couple times every year (Clevinger was based in Florida for the first decade of the strip's history) and there were usually a handful of personal crises that pushed back publication for a short time. Bizarrely, as the strip neared its end, 8-bit Theater was increasingly erratic in its update schedule, sometimes missing entire weeks.
Clevinger grew defensive after one of those update-less weeks, the result of computer issues at his new home. "I've given you eight years of some of the most consistent* work you've seen online. I don't think it's unreasonable to ask for a little patience from you here, in the final hours, when I miss an update for the simple reason that it's impossible to make one. Thank you." He did say in the asterisk footnote that "terrible work is still consistent work."
His other webcomic, Warbot In Accounting, however, is hit by this hard. First it was updating once a week, but quickly spiraled into "once very few months, if you are lucky." Supposedly this is because the artist has terrible luck and either loses all of his work or has severe financial problems. He seems to have learned from this however, as his other other webcomic is openly stated to have a one-month buffer, and will update on Mondays and Fridays, no exceptions.
Clevinger's case is somewhat amusing in the sense that the vast majority of his delays are caused by a Plague of Good Fortune. Specifically, it seems every time he makes progress on a project his various partners become too busy from other obligations (that actually provide a means of paying the rent, unlike the released-for-free Warbot and HIKYM) to actually do anything with Brian's projects. For instance, Zack Finfrock became busy with art commissions he pays for his lifestyle with and later got a job as a host of a webseries, and the co-writer/artist (can't remember which) of HIKYM got hired to work on actual print comics. Clevinger himself has his own highly popular print series to contend with, as well as the fact that Marvel has thrown him at least two miniseries to write for in the last year.
One member of a similar contest to the Daily Grind which had previously had a really bad history of schedule slips was Elf Only Inn. When it finally slipped after a rather good showing, the Lazy Grind runners were a bit slow to mark it off on the page, while some people mused in the shoutbox on the Lazy Grind page that, now that there had been a single slip, the comic creator (Sortelli) would probably not update for months. The shoutbox was removed and replaced by a temper tantrum by one of the Lazy Grind staff. In the end, Sortelli proceeded to not update Elf Only Inn for months immediately after his slip, and continues to post an average of one comic every three months or so.
To make matters worse, apparently the Grind itself has had a bit of a schedule slip. Kell Hound apparently won the contest when its last fellow competitor missed an update... back in April of '08.
Lazy Grind itself has finally been taken down, but it exists (somewhat) on the Wayback Machine.
El Goonish Shive went from updating every day, to every weekday, to Monday-Wednesday-Friday, to Tuesday-Thursday-Saturday, to at least 2 days per week with a filler. There are also several occasions where months passed between story updates due to problems in Dan Shive's private life. The worst slip was from September 2007 to January 2008, while Dan Shive was learning to color his strips with his new art style. The strip briefly went back to a regular Monday-Wednesday-Friday schedule, only to revert to filler and a new schedule which, in turn, collapsed. Another abortive attempt at Monday-Wednesday-Friday was made, but Dan's tablet PC (which he uses to draw) died, and we were in limbo before settling on another schedule (Tuesday-Wednesday-Thursday), and NP was revived.
NP went from claiming to be on a one week hiatus, to going years without updating, to being revived due to some of the milestones of Dan's Patreon campaign.
Starting in April '11, Shive started invertingSchedule Slip. Yes, he has missed a couple days due to tech problems, and people demanding a sketch of a certain panel, and he had a brief relapse into Slip territory in 2012, but he's actually gone back to four or five story comics per week, an update rate not seen in years. Then in August of 2014, when the first round of Patreon rewards kicked in, updates soared to thirteen per week - five story comics, five sketchbooks, and three NP strips. Towards the end it ate up Dan's buffer and some updates went up at eight or nine instead of midnight, and the Patreon was modified slightly to reduce future workloads.
The End Of Things last updated June 16th, 2010. After being on hiatus since November 18, 2009. And it was rather sporadic before then too.
Prior to getting its own site, Erfworld claimed to update three times a week on their comic page, but actually updated three times a month. It's an egregious example because it started out being hosted on the same website as The Order of the Stick and was originally brought in to compensate for its Schedule Slips.
Everlasting Wanderers started in 2002 with a 2-per-week schedule. It kept this for nearly a year, then slipped into once per week, then once a month... then once every few months. Then the website it was hosted on disappeared and it seemed to vanish from the web, only for the author to have reposted it on his deviantart. The longest break between comics has been 3 years. It's more or less considered an Orphaned Series, although it a new comic seems to have come out once in a blue moon. The author lampshaded this with his latest update: "see you next year!"
Exterminatus Now has suffered this steadily. It updates weekly at the weekend, though it's still spotty at times.
Fantasy Realms started off as a free comic, turned into a Wirepop launch series, gave a few months of regular updates, then fell into a black hole. It departed the site and has rarely updated despite multiple promises of new regular updates.
Often invoked by Femmegasm due to Robbie Allen's frequent health problems. A particularly nasty one came in July 2012, when a seizure resulted in him losing feeling in his arms. He often fills the void with fanart. He finally got on track, but ended the strip in February 2014.
The Fox Sister: The intended update schedule of one page each Thursday has several times been disturbed by Real Life.
Girly had a regular schedule once upon a time, but (as of the final chapter) updated as pages were finished. The author, Josh, acknowledged this and often apologized on his Twitter, and took a stab at himself in this update.
Goblins has run a bit late pretty much since the creator refined his art style back in Book One, but four days late was considered unheard-of and newsworthy when most of the party came to Brassmoon. Two years and eleven months later, the Brassmoon story arc finally came to a close. Updates a week late were practically the norm for most of that time, until Thunt made the comic his full-time job.
In March 2009, in response to emails requesting him to just post what he has instead of trying to make it perfect, Thunt published a series of blank panels.
It stabilized at a page Tuesday and a page Friday. But the donation-bar comic, Tempts Fate, stalled for several months starting in summer of 2010, and is almost invariably late otherwise. The main comic followed suit, stalling in February 2014. It returned in September 2014 but at a seriously slowed pace, sometimes as little as once a month.
Gone To Ground is notoriously bad at updating on a schedule, mostly because of its extremely detailed art style. On the other hand, the author is a good sport about it, with a banner on the site cheerfully proclaiming "updated bi-monthly."
Hanna Is Not a Boy's Name has gone on short hiatuses a couple times, and the author often apologizes for being late or worries her readers will get spoiled when she does stick to her schedule. By the end of 2011, there had been no updates to the site since mid-February, and no actual comic updates since the end of January.
Heart Core was expected to have at least one page released per week and an additional page when the donations from the fans reached a certain mark. These deadlines were met rather consistently, and slip ups were few and far between. But sadly, since 2013, due to Real Life problems that have affected the creator, Tara Welker-Stewart, the release schedule has been a bit inconsistent, something that the creator has apologized deeply for.
Andrew Hussie has an extremely ambitious update schedule for Homestuck. (There's a reason why MS Paint Adventures is the longest webcomic ever despite only being a few years old.) However, many flashes and important events have come out much later than planned. Often, this happens because he ends up writing a lot more between major events, so the webcomic still updates during the slippage. However, straighter examples have happened a few times: everything was put on hold for over a month to create "Cascade" (the general fandom reaction is that the flash was worth the wait), Hussie halted updates for days at a time to work on merchandise and the official books on several occasions in 2012, in summer 2013 there was a 2 month pause as he worked on the Kickstarter adventure game, and by October 2013 the comic was in "giga-pause" as he got the rest of Act 6 and all of Act 7 (which are implied to be fairly flash-heavy) ready in advance rather than posting as soon as the next page is ready.
Unavoidable with the second intermission. As an appropriately creepy flash, it was supposed to come out on Halloween, but a freak snowstorm blew into Andrew's city, cutting out his power for a few days. He was not happy about it.
The MINISTRIFE!!! flash in Act 6 Intermission 3 was intended for a Halloween release as well — a huge number of characters gather together, wearing a great variety of outfits, the gathering is mistaken for a costume party several times, and Damara asks "What's this? A Halloween orgy?" This time, the update was delayed by Hurricane Sandy, which flooded the server building in New York and resulted in days of downtime as the webhosting service tried and failed to run on generator power alone.
Instant Classic and Genrezvous Point alternate between 10 strips per week (seven IC, three GP) and posting nothing for months at a time. To be fair, the artist is a filmmaker and his bursts of "inactivity" are usually when he's working on a project.
Lackadaisy Cats' update schedule is the main criticism that is directed towards the comic. Rolling in at a little under 100 strips in 4 years (2006-2010) in the form of sporadic updates every few months, Lackadaisy's periods of inactivity drove some fans to declare the comic legally dead only to be proven wrong time and again. Luckily the comic has been updating with something resembling regularity since 2010, presumably when the comic was picked up by a publisher and became a meaningful financial venture rather than a pastime. The comic then slipped again, hard, with the the last two updates for actual story pages being in August of 2012 and February of 2013. Then a new page for the story has been added on the 21st of December, 2013; 2 months shy from being a year without an update.
Leve L updates as infrequently as once a year. The readers keep assuming it's finally become an Orphaned Series before being proven wrong.
The Life of Nob T. Mouse had a major bout of this when the series went on an unannounced hiatus between the final part of the Nasties! storyline in 1999 and the first episode of Pie Noon' in 2007, i.e. eight years'' later. This will hopefully not happen anymore however, since the comic reportedly now has a Strip Buffer.
Lewis Lovhaug's webcomic Lightbringer was always sort of erratic in its update schedule, often posting filler strips and missing the Wednesday update, and in December 2011, posted its first update in over a year. This is ironic when you consider that Atop the Fourth Wall itself is well known for having probably the most consistent schedule of any Channel Awesome series (in four years, Lewis has missed his self-imposed Monday night deadline less than a dozen times and actually skipped a week only once or twice).note This isn't counting the weeks where Lewis decides to riff on public domain PSA films from The '50s in place of reviewing a comic book; hell or high-water, something from him will get uploaded Monday night or Tuesday morning.
Life on Forbez updated once a day for a long time before updating less and less before going on long hiatus. It took almost 10 years to finish the first big story arc. The fans (and the author) know that updates can be fleeting. Since then the updates have become more regular.
Little Worlds updated twice a week for the first few months, then lapsed to once a week, then went a multi-month hiatus (without warning or explanation). It has since returned and begun posting once a week again. The head writer, Peter Chiykowski, claims that University got in the way.
The Longest Sojourn fell into a year of non updates in April of 2006 before finally getting sporadic updates in 2007, and getting slightly less sporadic updates from April 2008 onwards.
Much like the Pokémon-X example from later on the page, John Joseco also insists on having The Lounge pages appear on the days they were supposed to. The last page (which has been up for months) was February 16, 2009. This is mostly because JJ has become rather obsessed with a different series, although even there his art has become infrequent of late.
L's Empire is a strange example of this trope. Why? Because the authors weaponized it! Dark Star had become an author and, as a result, he could see the strip buffer. So the authors purposely posted the page showcasing his defeat late to keep him from planning accordingly. They were already suffering from this, which was lampshaded in both the first and third anniversary specials.
The Meek's author got a new job and after 01/03/12 no new pages were released until 10/15/12. The comic continued to release regularly once a week until November 2012, upon which the author suffered a colossal Creator Breakdown and didn’t update the comic again until May 2015. After that it updated sporadically, until the author put it on hiatus again in October 2017 in order to finish another comic project.
Maliki was updated sporadically in 2013, going on hiatus in 2014, with only one strip published this year, because the author was busy working on his other project Hello Fucktopia. The return of the comic was announced in January 2015, and it returned to its weekly update rhythm in March.
One of the major criticisms of MegaTokyo is its erratic update schedule. On a good month there might be two of twelve scheduled comics produced. This is particularly grating to critics who claim that the "simpler" artistic style - light pencil drawings - suggest a sacrifice in artistic quality for the sake of regularity... which means it fails on both accounts. Naturally, there's a lot of detail in those pencils, so it can be argued either way.
Also worth noting is that Fred Gallagher, writer and artist of Megatokyo, decided to quit his job and make the comic itself his profession. (Way before Dresden Codak did it.) However, unlike Dresden Codak, the update schedule didn't remain the way it was after Fred started devoting all his attention to it... it got worse.
Since the birth of Gallagher's son, updates have become even more infrequent and unpredictable, with the average by the end of 2008 hovering somewhere around one comic per week. The creator even changed the schedule to a two-per-week Tuesday/Friday schedule, and he can't even keep that up.
By 2010, a quick peek at the archives page shows the update schedule is down to 2-4 a month or worse, with frequent delays. This, combined with Webcomic Time means that a casual reader can check in on it once or twice a year and not miss much. However, this can be at least partly attributed to major health issues for both Fred Gallagher and his wife:
Piro's rant from November 2010 reveals that Sarah, the real life Seraphim and Fred's wife, was diagnosed with lymphoma. Despite her reasonably upbeat attitude, the impact this had on the comic's updates was profound.note To put this into perspective, Fred started one chapter in June 2010 (when his updates had already deteriorated to about one comic a week). In the nearly three years that followed, there were a grand total of just over 80 story comics, without getting even close to any sort of resolution. August 2011 was the last month to have more than four updates; December 2011 (and 2012) only saw sketches posted; March and April 2012 had only one comic apiece; May 2012 had four comics but June 2012 had no updates at all; 2013 averaged about one comic every two weeks. In real time, Piro and Miho spent nearly fourteen months in the public bath-house, a sequence that lasted around an hour or less in-universe.
Modus Operandi, which began in mid-November of 2010, managed to post seven updates before stalling out in mid-February. A four-month gap has finally been ended by a new comic posted in mid-June. Subsequent deadlines have been missed. No word on when (if) they'll go back to regular updates.
A Moment of Peace experimented with a 'whenever' schedule after the author found she produced more over a Christmas break when there were no deadlines. After producing a lot of comics under this new schedule, the comic went back to a Thursday-Sunday pattern.
MSF High has suffered from this a good few times, and has actually orphaned the previous version, HSCM, twice.
Neglected Mario Characters from 1997 until around 2004 updated regularly on a generally weekly basis. But after the creator graduated highschool he got less and less time for the site, and eventually vanished completely without any signs of what happened to him. The last six years or so have basically been nothing but comics made by fans wanting to continue all of the many stories he left hanging.
A recurring question on webcomic discussion boards asked, "Will Never Never ever ever continue?" Its main page declared a temporary hiatus from July 2008 to October 2010, after which the site saw a flurry of updates that were scheduled to bring about the conclusion of the story in January. Schedule Slip happened again, more than once, and the final page wasn't posted until March 17th of 2011.
Around late 2012, Erin Mehlos fell behind on her Strip Buffer for Next Town Over, partly due to having her first child. She decided to start posting a side-story vignette called "Genevieve" with a simpler artstyle and monochrome coloring while she built her buffer back up for the main plot.
No Pink Ponies still claims to update 4 times a week, but there were no new stripes for most of 2008. The author announced in mid-April 2008 that he was "bogged down by multiple other jobs", which were to be done by the end of May (''Marry Me'' only finished in late June). NPP was going again for a while, with the author promising to post a strip a day to make up for the break, but the revival consisted of 9 regular strips plus one "Sunday" strip, a news post from the author promising not to take a planned month's break, then another extended hiatus.
No Rest for the Wicked has repeatedly fallen into long, unannounced hiatuses since 2008, each one long enough to make it appear to be abandoned...right before it comes back from the dead again.
Not in My Backyard! started off on a schedule that, while somewhat irregular at times, averaged out to a reasonable number of strips per week. However, there were no new strips between June 16 and July 3, 2000, and from then until January 2001, there were only 17 updates (including only one strip between August 7 and October 3). The strip finally got back on something resembling a schedule in 2001, but abruptly ended that August.
The Order of the Stick once had a fairly strict three-times-a-week schedule. The author reportedly has a chronic illness, which lead to an "updates without warning" schedule hoping to average out to three times a week.
Before his "unspecified chronic but non-life-threatening" illness progressed to the point where it could randomly leave him bedridden for weeks at a time, he was extremely consistent, to the point of occasionally apologizing for being an hour or so late.
After a long hiatus because of a thumb injury, the characters broke the fourth wall about it, with Elan insisting on providing a recap comic since it had been so long for the readers.
Ozy and Millie once updated every weekday, Monday through Friday, with minimal interruption. Towards the end, the comic updated irregularly; creator Dana Simpson attributed this to waning interest. The series has since semi-officially ended: the main storyline has met a satisfying conclusion, but occasionally Simpson updates the site with a new drawing, and she has left open the possibility of more stories in the future.
Fans of PAWN had to wait two friggin years and for a site move before Anderson finally posted some new pages, and another extended hiatus began in August 2013.
Peter Is the Wolf has a once-a-week schedule; due to the writer and artist working on the pages separately, both of them having other projects to work on, and the comic itself generating little to any revenue for the creators, it's a pretty frequent occurrence to find out that a page is being delayed for the week.
Planet Zebeth had a fairly regular MWF updating schedule, along with several bonus strips celebrating anniversaries and the like. Activity has dropped off, mostly due to Real Life, especially when the author gets new video games, which is often explicitly stated by Kabutroid himself to the other characters. It also doesn't help that he's had to re-install Linux several times throughout the run, which actually drove a few story arcs.
Pokémon X insists on dating the comics on the days they should've come out (M-W-F update schedule)... which means that on March 20th, 2009, the next comic to have gone up was dated December 1, 2008. Yeah. To make things worse, the author has also begun writing the newsposts to go with when the comic should've come out. In March 2010, the newsposts were anticipating the author's return to school in August 2009. This is especially ineffective in regards to announcing the author's appearances at conventions that happened half a year ago. Lampshaded in the strip for August 17, 2009, which was posted on April 2, 2010.
Pokey the Penguin didn't see a single update in 2009. Starting in July 2010, the comic updated daily again.
Post Nuke hasn't updated since New Year's Eve 2010. The author's still sending us "news" type updates, though.
Missed a scheduled update for the first time ever on October 15, 2010 due to hand problems.
Prequel: The last main comic update was on October 31st 2015. Originally it stopped to let the artist get on top of setting out merchandise, but didn't start up again. It finally updated again on September 21, 2017, nearly two years after the previous update, and seems to have a semi-consistent update schedule.
Punch an' Pie has it so bad that there was practically a revolt in the journal comments section. New strips were originally promised in November, after delays ongoing since May. In December 2011 it was announced that the artist would be taking over writing duties as well. In January the artist announced he was working on the strips and would restart once a buffer had been built up.
Real Life Comics has rarely met its five-day-a-week schedule since 2011 or so, mostly due to Greg Dean's day job and caring for his daughter.
Clay Yount's Rob and Elliot, was originally running twice a week, then knocked back to once a week one to support the launch of Cosmobear (now an Orphaned Series). Despite the latter not updating for over two years, Rob and Elliot still stayed at its purported once a week schedule, then grew increasingly sporadic about whether it would update each week or not. The artist and writer finally killed it off for good in June 2012 with a simple gag strip that claimed the characters had now reached the zenith of comedy and could no longer continue.
The Saga of Earthsong started out at two days a week before running into occasional hiatuses. It now painfully creeps ahead at about one page a week, made only the more excruciating because two years into the comic's storyline, a publishing deal led the author to decide to completely reboot the entire comic...publishing at an even slower pace then it originally started. So despite cutting a tremendous amount of filler and excess exposition, the update schedule means the comic has actually taken longer to get to the exact same point in the storyline that it was at when the story was rebooted.
Scandal Sheet! seems to alternate between periods where Troy Smith swears he's turned over a new leaf, has a Strip Buffer going, and sticks hard to a thrice-weekly schedule for a few months...then declines...leading to month-long (or longer) gaps in the archives - and then he's back, "No really, I mean it this time!" This would be far less frustrating if Smith didn't like to write enormous, extended story arcs that take months of real time to complete even with regular updates. It seems the comic is more-or-less dead, with the last installment being dated Feb 16th 2009 and nothing since (despite posts from Troy claiming an imminent comic in April, then May, then late June, with very little heard from him since).
Secret of Mana Theater has had this happen a lot in the last few years. Heck, one of the bouts lasted almost three years before the series updated again, followed by another hiatus lasting many months.
Shadownova has missed a couple of updates in its MWF schedule so far but this is always followed by an apology, explanation and several pages uploaded at once to cover the missed updates.
The S'mores Metaphor, also known as F*** the Box!, underwent this. The author has stated it is due to illness, and seems rather fiery about updating as soon as s/he has recovered.
Sparkling Generation Valkyrie Yuuki, always erratic at best, has gotten even worse since the artist has shifted her attention to her paywalled erotic comics site, not that you can blame someone for prioritizing something that helps pay the rent.
Stage Select When Robot Masters Attack suffers greatly of this.
Obscure PokémonWidget Series webcomic Swageon and Glacigeon has had two after the beginning of a season.
Happened to Toki No Tanaka within its first month, with page 10 of a supposedly tri-weekly comic appearing almost three weeks after page 9.
Venus Envy has had this. It stopped updating in March 2010, then posted a single update two years later, and then nothing since.
Cheerfully acknowledged and lampshaded in this strip of VG Cats. Hell, he's even altered the banner so that instead of saying "Updates Monday" the text after the VG Cats part changes to things randomly selected things like "Error 404, Update does not exist", "I can't believe it's not Updated" and "Probably Not Updated Today" and quite a few more. His girlfriend has claimed on her website that Scott actually does write around a comic per week, but is often dissatisfied and discards them.
Happened to Wayward Sons in an especially frustrating manner: the artwork and writing are generally of very good quality and it resembles a full print comic throughout, and it has had daily updates (weekends included) for slightly more than two years. However, sometime during August 2012 and continuing ever since, gaps of varying width started to appear between the updates, the pauses ranging from a week to more than two months. The highly frustrating part is that this was done without any announcement whatsoever, with the blurb saying "Updated daily" a full three months into the irregular "schedule", and that the writer, on the comic's Facebook page, explicitly claimed several times that they were to return to daily schedule soon and that a lot of buffer material had been made. After one such announcement, the comic actually was again updated daily...for about a week, then disappeared without any warning for another two months. It is still being updated, about four or five times per month, but without a schedule, and the blurb has changed to "with occasional updates" - however, the FB page still proudly claims that it is updated "daily". In the recent months, there have been no explanations or announcements whatsoever - pages simply do go up at some point while all questions about the cause of the delay are ignored. It may not sound as bad as many other examples (it IS still running, and there is at least one update per month after all), but it's the contrast between the flawless daily schedule for several years and the current situation as well as the total creator-fan communication breakdown that makes it so jarring.
Both The Wotch and its spinoff Cheer! had a highly erratic schedule that could drop out for months at a time without notice, and even in normal times easily missed half their updates on a poor week. Then The Wotch crashed entirely, due to Creator Breakdown. It returned after more than a year with a new artist, and has managed to continue on roughly weekly during its arcs (however, there still can remain long periods between arcs). In the meantime, Cheer! stopped updating only returning for one strip after more than a year before finally fading away.
WTF Comics has, at times, gone for months without an update.
A few years ago, the fiancee (now wife) of the creator of xkcd was diagnosed with stage 3 breast cancer (despite being relatively young and having no family history of the disease). He used to do a daily update of the webcomic, but following the diagnosis, he cut back the webcomic updates to Monday, Wednesday, and Friday, so he could be there for her more. The update schedule has remained that way ever since.
Xylia Tales. Classic example – regular updates gave way to irregular but frequent, then to less frequent, then a two-month pause, and then an official "hopefully" one-month hiatus... which never actually ended. BL Jacobs filled in with blog posts, concept art and sketches (along with an increasing number of rebuttals to unhappy readers), but this petered out in November 2011, mainly because there was no more news or progress to update people on. The last actual story page appeared in January 2010. note BL Jacobs has gone down this road before. Talismen: Return of the Exile was an earlier webcomic of hers, with similar themes and full-page colour layout. It also suffered a similar decline, the main difference being that she did formally and officially decide to abandon it. A new blog post appeared in June 2013; while BL Jacobs is still active and committed to finishing the story, changes in her personal life and outlook mean that she is no longer able to relate to the romantic basis of the story so far, and is looking at a rewrite of some sort. She has already made several attempts at this. Don't hold your breath, folks...
This has happened to Zebra Girl so often that author Joe England changed the comic's header from reading "Updated Fridays" to "Updated Unpredictably". In recent months, he has managed to publish something, if only a couple of panels, more-or-less weekly.