Cheers Oral History - GQ October 2012: Movies + TV: GQ:
David Lee (writer-executive producer): On some shows, [the producers] say, "Oh, you gotta have 10 jokes per page." Glen and Les would go, "You know, it's better to get rid of the 'Fifty percenters,'—the jokes that are just chuckles—and be satisfied with the hundred percenters." If you have enough lesser jokes in the way, you actually start diminishing the value of the really good ones.
Tim Berry (producer-director): They threw out more great material than you'll ever know, because every day, they'd be rewriting and honing and polishing. Some things that would get a huge laugh at the table were gone by day three or four.