These days, television series are lucky to get a second season, let alone a third, fourth or fifth.

So for "Saturday Night Live" to hit 40 seasons when it returns Saturday night, is certainly a reason to celebrate the comedy series, which debuted on Oct. 11, 1975, under the guidance of Lorne Michaels.

Despite a rotating cast, changing viewing patterns and ever-increasing competition, "SNL" has remained a relevant television staple, as much a water cooler topic as it was in the late 1970s.

"I think one of the challenges is that people have so many outlets to hear everybody's takes on the same subject matter," said Kenan Thompson, the current longest-running cast member, starting back in 2003. "And that is a tough thing for the show, because the show is topical a lot, but it's also special because we get the experience of doing a full-on live comedy show with wigs, makeup, sets, costumes and stuff like that. ? It's still got its own sensibility, and I think that's what keeps it standing in a special place for people to tune in and see what we're talking about."

ScreenCrush.com senior editor Mike Ryan, who has been covering "SNL" since 2010 at Movieline, Huffington Post and ScreenCrush, said that part of the show's enduring appeal is that, as a live show, "people like knowing that 'technically' anything can happen."

And a lot of shocking things have happened, from errant curses dropped live on air to Sinéad O'Connor tearing up a picture of Pope John Paul II to Ashlee Simpson getting caught lip syncing and dancing a jig before leaving the stage.

Of course, it's the comedy that people come back for, with memorable sketches and jokes that have become part of our cultural lexicon. More Cowbell. Wild and crazy guys. Well, isn't that special. Strategery.

"I think when Chevy Chase said, 'I'm Chevy Chase and you're not' on 'Weekend Update,' that solidifies it for me," said Jay Pharoah, who has been with the show since 2010.

Cast member Aidy Bryant, who started in 2012, said one of her most memorable moments comes from a political parody, which you could argue is the show's real bread and butter.

"All that stuff with Palin was so thrilling," Bryant said. "It's just a perfect expression of what the show can do. I think that was something that I'll never forget."

 

 

The only constant is change

Since it started, there have been 140 Not Ready For Prime Time Players -- and it's a regular who's who of the top comedians of the last half century, from Bill Murray to Dan Aykroyd to Eddie Murphy to Julia Louis-Dreyfus to Will Ferrell to Tina Fey.

Ryan said that he believes "Saturday Night Live" has remained relevant for so many years by rotating its cast.

"[John] Belushi leaves, Eddie Murphy arrives. Murphy leaves, Dana Carvey arrives," Ryan explained. "Replenishing the cast has been 'SNL's' greatest asset, and if you'll notice, when "SNL" is at its worst moments ? the solution is to almost start over with brand new casts. And it has always worked."

Thompson believes that a lot of the credit for the longevity of the show comes from Michaels' ability to constantly find the right people.

"I feel the world is filled with talented people and 'SNL' is lucky that it has that kind of a platform that we end up cycling people in and out," he said. "There's a ton of comedians that deserve a chance."

 

 

Remaining relevant

When "Saturday Night Live" started, there were late-night talk shows like "The Tonight Show Starring Johnny Carson" with comedy monologues. But in terms of topical humor on TV, "SNL" was pretty unique.

These days, comedy is everywhere, from one of many talk shows -- both daytime and nighttime -- Twitter, podcasts and "The Daily Show," not to mention the existence of Comedy Central, a network devoted exclusively to making you laugh.

That's a lot of competition. But the cast members don't seem too concerned.

"I don't believe it's a challenge," Pharoah said. "I believe it's more of just us paying attention and being hip to what's happening in pop culture. So I don't think it's a challenge, it's just somebody on the staff paying attention to what's happening. ? Then you evolve, just like you're supposed to."

 

 

40 years later

"Forty years means that this is the longest comedic running show on television, and we're still going strong," Pharaoh said.

But the big question is, what happens when Lorne Michaels, 69, is no longer running the show? "SNL" continued when Michaels briefly wasn't running it from 1981 to 1984.

Ryan speculated that NBC will try to continue the show, "but who knows if that will work?"

Ryan interviewed Tina Fey for The Huffington Post in 2013, and when pressed with the question of an "Saturday Night Live" without Michaels, Fey said, "'SNL' is so defined by Lorne's taste and his sensibility. ? He is the center of the show, and I think it should just -- when he wants to stop, it should just stop."

Bryant, however, sees the show continuing on.

"I assume we'll all be robots and everything will happen via computer," she said. "But, I don't know. I'm happy to be even a part of [seasons] 40 and maybe 41, so I can't even imagine what it would be another 40 years from now."

Either way, 40 years is a heck of an impressive run, and it wouldn't be surprising to think that we might one day be celebrating 50, 80 or 100 years of "Saturday Night Live."

"It's remarkable, because imagine any television show starting today," Ryan said. "Would we ever think, 'I bet that's still on in 2054?'"