Today is the 25th anniversary of the debut of The Simpsons, which aired its first episode as a Christmas special on Dec. 17, 1989. Yes, you are getting old.

But, weirdly, The Simpsons has found its way past its mid-run slump and is now showing its strengths. The Every Simpsons Ever marathon that ran this summer on FXX offered 12 straight days of the ultimate Simpsons binge and proved my point. Coverage of the marathon in the media largely ceased after the first weekend was over, as the show had exited its first eight seasons, usually accepted as the series' golden age. But viewership actually kept going up, with FXX announcing that each of the first six days topped the previous day.

The later episodes have been shown in syndication more often in recent years, which may have created a greater affection for them among the general populace than among Simpsons diehards, or the number could have kept growing just because people found out about the marathon and wanted to get in on the fun.

But after watching so much of that marathon, I think there's maybe a different reason for this: The Simpsons has, for the most part, stayed a pretty good show, and having it on while doing other things is usually a safe bet.

This goes against not only conventional TV wisdom but my own previous opinions, which held that everything after, say, season 10 was very hit-or-miss. And, yes, there are more bum episodes in the last 17 seasons than there are in the first eight, and there's definitely a sense that the show has missed a step since those early days of its run. But this would be inevitable for any show that ran for 25 seasons, and that The Simpsons has managed its decline so gracefully is arguably an even greater accomplishment than those near-perfect first eight seasons.

Yes, the show repeats itself a fair amount, but it would be hard for it not to. And, yes, the show has sort of lost a point-of-view character, as its writers have aged past first the Simpson kids and then even the Simpson parents. Many stories in its later years tend to be along the lines of "Can you believe things are this way?!" and have the tone of a particularly perturbed anecdote in the "Life in These United States" feature in Reader's Digest. All of these things mean it's hard for the program to create classic episodes week in and week out now.

But what the marathon underlined for me, more than anything, is that the series has attempted to stay true to its characters, and that it still takes chances, especially in its visuals. Both of these things are immensely important to its longevity, and the fact that it remains a pretty reliable form of entertainment from week to week. Seeing all of the episodes one after the other made the continuum that much more apparent: the show started great, became absolutely brilliant, then declined back to just great, before taking a few seasons to find a plateau of better than average.

There was a time when the show flirted with genuine badness, right around the first half of its second decade. Seasons 11 through 15 are far spottier than the other seasons, yet they still possess classic episodes like "Behind the Laughter" and "HOMR" (the one where Homer is revealed to have a crayon stuck in his brain). This is also the period when the series would sell out essentially any of its characters for a flight of whimsy, however, and that would have been a dangerous trend had it continued.

But from season 16 on, the show has found its level and kept fairly consistent. And especially with the shift to high-definition in 2009, the series found a new way to cram its frames full of visual gags. Some of these gags miss, to be sure, but that as many of them hit as they do this late in the show's run is to be commended. It's also become more playful structurally, doing whole episodes in complicated storytelling structures, or depicting events in Lego.

But what's most impressive is that the series is still telling emotionally resonant stories about these characters, and that it's opened up the ensemble so much that it has turned into a loose anthology show about the people of Springfield. (This very idea was once proposed for a Simpsons spinoff.) Episodes like "Holidays of Future Passed," or "Brick Like Me," or "A Totally Fun Thing That Bart Will Never Do Again" or "The Squirt and the Whale" have the kind of earned pathos to them that can only come after characters have literally decades of history behind them.

So it's worth checking out later season episodes as they pop up in reruns. Sure, they won't be as blindingly brilliant as the show's best days, but there will be more in there to like than to dislike. The show is no longer perfect, but it's still solid entertainment. And making that happen is harder than it would seem.