It certainly wasn’t easy for NBC to determine which of its Thursday lead-out sitcoms were merely timeslot hits and which had a genuine, dedicated fanbase. For new Thursday sitcoms like Union Square and the U.S. version of Coupling, the ratings made this distinction clear quite quickly; for many others, however, it was far less obvious.
In my view, Rules of Engagement was the quintessential timeslot hit, and CBS treated it as such, frequently shifting it around the schedule. CBS had originally intended for The New Adventures of Old Christine to be the major hit following Two and a Half Men on Mondays. However, Rules of Engagement performed well enough as a midseason replacement in its assigned slot that it was repeatedly renewed for midseason—often returning to the air even earlier than planned whenever a new sitcom flopped. This happened first with Worst Week, and the following season with Accidentally on Purpose (created by Knots Landing sweetheart Claudia Lonow). The next season, Rules of Engagement was included in the fall schedule—paired with How I Met Your Mother as a lead-in—but later in the season, it took over the slot following The Big Bang Theory after the failure of $#*! My Dad Says. The following season, Rules of Engagement once again stepped in as a replacement—this time for the unsuccessful How to Be a Gentleman—following The Big Bang Theory on Thursdays. Since CBS clearly didn’t place much long-term value on Rules of Engagement despite its success in many different timeslots, the network gave the coveted post-Big Bang Theory position to Rob—which turned out to be yet another sitcom flop for CBS—while Rules of Engagement was renewed once again. In the subsequent season, Partners failed in the slot following How I Met Your Mother, and Rules of Engagement stepped in, delivering significantly better ratings. Nevertheless, the sitcom was canceled after this seventh season—partly because the show had finally reached the episode count required for a syndication deal.
As for dramas, I would argue that The Guardian was a timeslot hit, airing on Tuesday nights at 9:00 PM between JAG (and later NCIS) and Judging Amy. CBS assumed that The Guardian didn't have a large enough fan base to survive a less favorable time slot, so they didn't even bother trying and cancelled The Guardian after three seasons.
It’s striking to me how fondly I remember shows that were timeslot hits—yet when you revisit them years later, they don't hold up nearly as well. That’s how I feel about The Outer Limits (the 1995 TV series). In its early seasons, The X-Files was a huge success in my home country, Germany, but it initially struggled to find the right lead-out show. In the first season, The X-Files was followed by NYPD Blue, and in the second by Renegade—neither of which really paired well with The X-Files. It wasn't until The Outer Limits took that lead-out spot that the ratings became nearly as strong. I remember how much I enjoyed watching The X-Files and The Outer Limits back-to-back—it always felt like a fantastic evening of television—but if I watch The Outer Limits today, that excitement has completely faded.
