A rerun or repeat is a re-airing of an episode of a media (usually television) program. The invention of the rerun is generally credited to Desi Arnaz. Some viewers find reruns annoying, although many viewers appreciate the opportunity to re-watch a program they enjoyed or watch one they missed the first time round. There are two types of reruns, those that occur during a hiatus, and those that occur when a program is syndicated.
In the UK, the word "Repeat" refers only to a single episode; "rerun" or "rerunning" is the preferred term for an entire series/season. "Repeat" is also used to refer to programs shown less than a week after the original broadcast, before the next episode of the series.
Reruns in the United States
In the United States, most television shows from the late 1940s and early 1950s were performed live, and in many cases they were never recorded. However, television networks in the United States began making kinescope recordings of shows broadcast live from the east coast. This allowed the show to be broadcast a few hours later for the West Coast. These kinoscopes along with pre-filmed shows and (later) videotape paved the way for extensive reruns of syndicated television series.
In the United States, currently running shows will rerun older episodes from the same season in order to fill the timeslot with the same program. This is often done for headliner shows because the length of the year (52 weeks) is far more than the length of a pick-up (13 weeks) or a full season (around 24 weeks). Shows will tend to start re-running episodes around November and show only reruns from mid-December until Sweeps Week in February (where a show will return to new episodes in order to spike their ratings). This winter phase is often used to trial new shows in order to see if they deserve a 13-episode run. Headliners will return from February Sweeps until May Sweeps, with only limited reruns used. These are more frequently referred to as repeats, with reruns the term more commonly used for syndicated programs.
A television program goes into syndication when many episodes of the program are sold as a package for a large sum of money. Generally the buyer is either a cable company or a host of local television stations. (Or, beginning in The New '10s, a streaming service such as Netflix or Hulu.) Often, programs are not economical until they are sold for syndication. Unfortunately since local television stations often need to sell more commercial airtime than network affiliates, syndicated shows are usually cut to make room for extra commercials. Often about 100 episodes (four seasons' worth) are required for a weekly series to be rerun on a daily schedule (at least four times a week). Very popular series running more than four seasons may start daily reruns of the first seasons, while production and airings continue of current seasons episodes.
No-one anticipated the long life that a popular television series would eventually see in syndication, so most performers signed contracts that limited residual payments to about six repeats. Exceptions have included Don Adams for Get Smart (who smartly chose co-ownership over a higher immediate salary) and Dawn Wells for Gilligan's Island. After that, the actors received nothing and the production company would keep 100% of any income. This situation went unchanged until the mid-1970s, when contracts for new shows extended residual payments for the performers, regardless of the number of reruns.
TV Guide originally used the term rerun, but abruptly changed to repeat in the early 1970s, apparently as rerun had developed a negative connotation.
Other TV listings services and publications, including local newspapers, would often indicate reruns as "(R)"; since the early-2000s, many listing services now only provide a notation only if an episode is new ("(N)"), with reruns getting no notation.
Repeats in the United Kingdom
In the United Kingdom, most drama and comedy series run for shorter seasons - typically 6, 7 or 13 episodes - and are then replaced by others. An exception is soap operas which are either on all year round (for example EastEnders and Coronation Street), or are on for a season similar to the American system.
As in the US, fewer new episodes are made in summer. Until recently it was also common practice for the BBC, ITV and Channel 4 to repeat classic shows from their archives, but this has more or less dried up in favour of newer (and cheaper) formats like reality shows, except on the BBC where older BBC shows, especially sitcoms like Dad's Army and Fawlty Towers, are frequently repeated.
Syndication did not exist as such in Britain until the arrival of satellite, cable and later, from 1998 on, digital television, although it could be argued that many ITV programmes up to the early 1990s, particularly imported programming was syndicated in the sense that each ITV region bought in some programmes independently of the ITV Network, and in particular many programmes out of primetime made by smaller ITV stations were "part-networked" where some regions would show them and others would not. Nowadays the UK has many channels (for example UKTV Gold) which repackage and rebroadcast "classic" programming from both sides of the Atlantic. Some of these channels, like their US counterparts, make commercial timing cuts; others get around this by running shows in longer time slots, and critics of timing cuts see no reason why all channels should not do the same.
Early on in the history of British television, agreements with the actors' union Equity and other trade bodies limited the number of times a single programme could be broadcast, usually only twice, and these showings were limited to within a set time period such as five years. This was due to the unions' fear that the channels filling their schedules with repeats could put actors and other production staff out of work as fewer new shows would be made. It also had the unintentional side effect of causing many programmes to be junked after their repeat rights had expired, as they were considered to be of no further use by the broadcasters. Although these agreements changed during the 1980s and beyond, it is still expensive to repeat archive television series on British terrestrial television, as new contracts have to be drawn up and payments made to the artists concerned. Repeats on multi-channel television are cheaper, as are re-showings of newer programmes covered by less strict repeat clauses. However, programmes are no longer destroyed, as the historical and cultural reasons for keeping them have now been seen, even of the programmes have little or no repeat value. (And also because modern digital storage is much cheaper and takes up much less space than film or video tape.)