There are several ways that
television programming can be syndicated. First-run programs in
syndication, such as
Xena: Warrior Princess and
Star Trek: The Next Generation when they were new programming, typically air once a week in a set (or sometimes roaming)
timeslot set up by stations to either compete with a
network running prime-time programming or prior to network prime-time programming as a lead-in (in the case of a network affiliate). Stations pay a set rate per season for the show, often in multi-year deals, and can often negotiate for a secondary airing of the newest episode sometime during the week.
Sitcom reruns, such as Seinfeld and The Simpsons, typically air between five and seven times a week (often in doubled-up timeslots, allowing stations to schedule an hour block of a popular show for a total of 7 hours of a half-hour sitcom per week). Typically these reruns are bought up by network affiliates who use them to lead into prime-time programming, figuring that if viewers come to watch Everybody Loves Raymond then they might stick around to watch Temptation Island. Sitcoms typically enter syndication when they produce approximately one hundred episodes which is deemed the minimum amount of episodes needed to be able to program seven hours a week of a show and not subject the viewer to the same episodes over and over again. A show like The Simpsons, which clocks in at over 300 episodes, looks much more attractive in syndication than a show like Futurama which only produced 72 episodes before it was canceled. When a sitcom rerun enters syndication the available episodes and their broadcast dates are determined by the owner of the show, but after a year or so of being in the syndication system local affiliates are typically allowed to set their own schedules and air the available episodes in any order they please. Some cable channels are joining the sitcom syndication game, such as TBS which currently airs reruns of The Drew Carey Show, Home Improvement, Friends, and Seinfeld five days a week in a seamless three-and-a-half hour block. TBS has even been experimenting with running Seinfeld reruns in primetime to compete with new programming from the networks. TNN has had great success with their marathon airs of Star Trek: The Next Generation, often running over fifteen hours of the series a week. Even shows that have not produced the 100 episodes needed for syndication have found success on cable, such as Cartoon Network's acquisition of Futurama reruns.
Another common type of syndication programming is movies. Syndication is one of the last stops on the life cycle of a movie, starting in the theater and then going to home video/DVD, Pay Per View, the network television premiere, and then to syndication. Syndicated movies are treated somewhat like the first-run programmming mentioned above in that broadcast affiliates can purchase the air rights to show a movie during a certain timeframe. These movies are often scheduled for weekend afternoons and late nights. Like most movies on cable, the films have been heavily edited and broken apart into short pieces to allow for commercials, with most films being either cut down to fit a 90 minute block + 30 minutes of commercials or, in the same of longer movies that cannot be cut down so easily (such as Terminator 2: Judgement Day) a 135 minute block + 45 minutes of commercials. The syndicated movie is appealing to affiliates because, even though the syndicator fills some of the commercial time themselves, the bulk of the commercial time is available for sale by the station airing the film. Network movies (such as airings of Star Wars: The Phantom Menace during primetime on FOX) typically leave local affiliates little time for their own commercials due to the network and the film's distributor collecting most of the commercial time (and money). Often stations can purchase multi-year syndication deals for movies, meaning that they can, for example, purchase the rights to the Phil Hartman/Sinbad comedy Houseguest for three years provided that they only air it during the month of February each year. Also, because each station can buy into the airing rights for the movie, it's not uncommon to see the same movie appear on different stations during different times of the year (or, in some cases, week). Cable channels typically have ties to a movie's production house or distributor which means that since the network and the movie are owned by the same studio, they can air the movies they own as much as they like (which explains why Warner Bros.'s TNT thrives on airings of Lethal Weapon 4 and John Wayne westerns).
While the majority of network affiliates thrive on their parents' programming, there are still a large number of broadcast stations that rely only on syndication and their own local productions to fill their schedules. Despite the power of the networks and cable programming, syndication remains a major way for stations to fill programming time.