TV shows can't last forever. And the longer a show is on, the more likely it is that it's closer to its series finale than not. Take, for example, the NCIS franchise. It's already said goodbye to one spinoff (New Orleans, in 2021), and NCIS is going into its 20th season and Los Angeles into its 14th. Could either end in 2023?

"We hired a fantastic writer named Marco Schnabel a couple years ago and he was asking me, 'When are we gonna get our pickup?' And half-jokingly, I said this to him, but also half-seriously, 'What do you mean the pickup? … There has always been NCIS, there will always be NCIS," executive producer Steven D.

Binder tells TV Insider. "And that's just how we feel. Now that may not be, but when it's been 20 years, it's hard to imagine that this year will be the year it ends. So, if people keep watching, we're gonna keep making the show, and people keep watching."

He knows that like all shows, NCIS' ratings do drop each year (and this one featured a move to Monday nights), but what's "mind-boggling" is that "it's been 13 seasons we've been on top, and I don't know that even I'm going to truly understand what that means or how special this is or how rare this is or how fortunate we all are until it's over or I've left because I believe that I'll leave and the show will keep going.

I just don't ever see this show ending. I think if we keep telling good stories, I think the show keeps going."

The real test for the show came this past season, when Mark Harmon, who played Leroy Jethro Gibbs since the backdoor pilot on JAG, exited four episodes in. But the show has continued to do well. "It's really astounding. I was hopeful — because I had to be, and it's so not my nature — that we would still manage to keep going without Gibbs," Binder admits.

"We've lost Abby [Pauley Perrette] and we lost Tony [Michael Weatherly] and we lost Ziva [Cote de Pablo] and we've lost Kate [Sasha Alexander]," he continues.

"We've lost a lot of other people who were if not the cotton, they were the stitching, Mike Franks [Muse Watson] and all of those guys and Jenny Shepard [Lauren Holly]. We've lost a lot of people, but Gibbs is Gibbs, is this the one that's gonna break us? And it wasn't." So who might be? "It's gonna be Director Vance's assistant — when they go, that'll be the end of the show."

Meanwhile, NCIS: Los Angeles executive producer R. Scott Gemmill shares that the feel-good Season 13 finale was "partially because we didn't know if we were going to be renewed." On NCIS: LA, "we always keep it [in the back of our minds]" that a season could be the last, he says. "It'll be sad, but everything has to come to an end at some point."