best TV shows of the 21st century. 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 program 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 programs 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 programs covered by less strict repeat clauses. However, programs are no longer destroyed, as the historical and cultural reasons for keeping them have now been seen and the cost to maintain archives is now far less, even if the programs have little or no repeat value. See also First run References Television terminology