It's Always Sunny in Philadelphia creator Rob McElhenney recently celebrated the upcoming 13th season premiere of his series with a sorta tongue-in-cheek post in which he joked the FXX comedy was "finally halfway through" its run. But his nod to Sunny's longevity is no joke.

Returning with its 13th season Sept. 5, the series ranks as the longest-running live-action comedy in cable history. And when Sunny debuts its previously announced 14th season (presumably in 2019), it will tie The Adventures of Ozzie and Harriet as the longest-running live-action comedy in TV history. And to McElhenney's point, the 13th season is still as creatively fresh and funny as it was a decade ago as new episodes offer timely takes on everything from the political climate in the age of Trump to the Time's Up movement.

"I think we're the only show sort of grandfathered in to being able to speak to some stuff that people needed a little bit of a laugh about," star Charlie Day tells The Hollywood Reporter. "And we hopefully [will] be able to provide it without ruffling feathers too much."

Day is quick to share credit for Sunny's ongoing creative success with FX and its younger-skewing sibling FXX's "model of really writing a check to creative people and letting them make what they want."

To hear Day and co-star Kaitlin Olson tell it, the secret to the show's success is the cast and creators' decision to prioritize the show while also pursuing projects outside of Sunny, which adds creative fuel for everyone involved in the long-running favorite about a group of friends (played by Day, Olson, McElhenney, Glenn Howerton and Danny DeVito) who run a Philadelphia bar.

"Experiencing something else always highlights all of the qualities that I'm really grateful for," says Olson, who spent two seasons starring and exec producing Fox comedy The Mick (which was also exec produced by brothers and Sunny EPs Dave and John Chernin). "You always kind of feel like you're coming back home when you're back together. Another thing that made [season 13] special was taking a year off. We weren't burned out to begin with, but taking a full year off, everyone was just so fresh and excited to come back. It's just so easy to fall right back into. It's like just sitting down with old friends. It's very easy, and we all kind of know what we're doing."

Olson's next project outside of Sunny also has strong ties to the show: an untitled Fox comedy pilot co-written by her husband, McElhenney, and their Sunny cohorts Nick Frenkel, Day and Howerton.

The rest of the Sunny cast also has a full slate of moonlighting ventures: Howerton will star in a second season of NBC's Seth Meyers-produced comedy A.P. Bio; McElhenney and Day are writing a comedy set in a video game studio for Apple; McElhenney is an exec producer on Spikeface, an upcoming animated comedy on Rooster Teeth's streaming service; DeVito has roles in Tim Burton's Dumbo live-action movie and The One and Only Ivan animated film. Day also exec produces Fox's multicamera comedy The Cool Kids.

"Obviously, it's easy to get complacent in this business, or in anything in life," says Day, who's also keeping up appearances on the big screen, reprising his voice role as Benny the Spaceman in February's The Lego Movie 2. "Going and doing some other projects allows us to explore our creativity outside of Sunny. But we also know that to be able to write what you want and say what you want and use the music you want and use whatever camera angle you want, it's rare. You have to do a lot of begging and you have to get a lot of approval every step of the way any time you make something. So it's such a gift for us to return to Sunny and say, 'Here's a platform where we have a supportive network to really allow us to make the show however we want.' When we're fortunate enough to work on some other people's projects, we try some things. And it's always nice to be able to come back and have the keys to our own kingdom, so to speak."

Olson notes she and her Sunny cohorts put forth a concerted effort to juggle schedules and ensure that everyone has time to pursue other professional gigs, as well as their personal lives. When It's Always Sunny premiered in 2005, none of the four original castmembers (DeVito joined in season two) had children. Now they all do.

"I think in the beginning, we tried to squeeze in other things around Sunny, and then I had a baby, and we had to push a month. Danny was doing a movie, we had to push a month. Charlie was doing a movie …," Olson says. "So, at some point in there it kind of turned around a little bit, where it was like, we really love this, and we also want to have families, and we want to have broader careers, and so there's got to be a way that everyone can get everything that they want, because this is our life. And Sunny is a comedy, and we're supposed to be happy. You can't show up to something like this not wanting to be there, or in a bad mood. It doesn't work. Part of why our show works is, I think you can tell, we're legitimately having a fun time in these scenes. This wouldn't work if we were unhappy, or not wanting to be there."

Finally, as both TV creators and viewers can attest, the shorter seasons for cable programming — since season eight, Sunny has aired 10 episodes per cycle — is a boon to maintaining quality. "[Rob, Charlie and Glenn] only want to do 10 episodes a season, and that's just so smart, and it's so great that we aren't forced to do more than that," Olson said. "I think it's impossible to crank out 23 amazing episodes a year. There's going to be some stinkers in there."

And there are no signs of stinkers in the first handful of season 13 Sunny episodes provided to press. In addition to the timely issues, other storylines will find the gang competing with each other in an escape room game, ruining guest star Mindy Kaling's efforts to make Paddy's successful (with the assistance of a fascinatingly accurate Dennis doll), celebrating the Eagles' Super Bowl win with a two-part Super Bowl episode, and doing a "reboot" of season 10's classic opener, "The Gang Beats Boggs," in which Dee, Artemis (Artemis Pebdani), Waitress (Mary Elizabeth Ellis), Mrs. Mac (Sandy Martin) and Charlie's mom, Bonnie (Lynne Marie Stewart) also embark on a cross-country flight and attempt to outdrink Major League Baseball Hall of Famer Wade Boggs.

Given the creative freedom and flexibility that comes with Sunny, can McElhenney's co-stars envision a scenario where season 13 really is the show's halfway point? "I certainly have moments where I think, 'How much of it can we keep doing?'" Day said. "But then every time we get together and make this show in what seems like a little bubble, by the time we're done, it's rewarding to look back on a season and give it to the fans. I'm still enjoying making the show, so who knows how long."