Time works funny on TV. With serialized dramas like Lost, where entire seasons unfold over just a few weeks, it was a struggle for the writers to figure out how to keep their lead child actorknowing that he could hit his growth spurt at any moment. For weekly sitcoms, it's easier because they generally take place in real time, with the characters experiencing the changing of the seasons along with the viewers at home. It allows kids to age naturally on screen, even if it feels too fast for comfort. (Carl and Debbie in "Shameless," for example, go from innocent kids to teenage balls of rage in the blink of an eye.)

Although the early seasons of "Young Sheldon" moved at the easy pace of a typical sitcom, with its child characters aging a year with each season, it changed things up in later seasons. Suddenly, the writers start stretching the timeline so that Sheldon stays at 13 and 14 longer than he normally would have. The result is that Sheldon begins the series as a 9-year-old (about the same age as actor Ian Armitage) and ends with Sheldon at 14 (although Armitage was now 16).

The reason they did this is because Young Sheldon, who is a fan of The Big Bang Theory legend, had a clear expiration date set from day one. The producers and writers always knew that George Sr. (Lance Barber) had to die when Sheldon was 14 years oldand they knew Sheldon would also transfer to Caltech when he was 14. The writers knew the series couldn't continue with Sheldon separated from his family and George Sr. living six feet under, so they delayed these canonical events as long as possible. Honestly, it's hard to argue with the results, since the actors for Sheldon and Missy (Regan Reward) both still went 14 in Season 7. It's not something that requires a lot of suspension of disbelief, to say the least.

Of course, "Young Sheldon" was just following in the tradition of many other sitcoms that messed with the times, often to absurd degrees. That '70s Show somehow managed to stretch the last four years of the '70s into eight seasons, to the point where the gang celebrated Christmas too often to make sense. A generation earlier, the hit series "M*A*S*X" covered the three-year Korean War over 11 seasons, asking viewers to accept that the war was so stressful that it caused some of its main characters to age. three times faster than an ordinary person.

Then there are the animated sitcoms, which don't need to age the characters at all. Bart Simpson has been trying to get out of the fourth grade for 36 years at this point (though he recently turned 11 in the show's 36th season premiere), just as Stevie Griffin (who is technically my age, born in '98) is doomed to be a baby forever. Animated sitcoms tend to adopt a floating timeline style, which leads to awkward moments where characters' backgrounds are constantly updated to match the times. So Homer Simpson, who started out as a baby boomer, is now a millennial whose Teenage flashbacks show him acting like a total '90s kid.

While it's not a sitcom, Stranger Things is probably the best modern example of a TV show struggling hard to fight the ravages of time. Those child actors are nearly nine years old going into season five, although the characters themselves (many of whom haven't yet hit puberty in season one) are supposed to be only about four years old. The show seems to address this a bit with its own fifth and final seasonwhich is expected to be set 18 months after season 4, but the awkwardness is still impossible to ignore. Stranger Things is still a fun show, but with its long production runs clashing so heavily with the canon timeline, it makes it much easier to appreciate Young Sheldon for its consistent annual schedule. The Big Bang Theory spinoff may have played a little loose with the timeline in recent years, but it could have been a lot worse in that regard.