Disclaimer: For this article, I focused on hit comedy TV classics that are at least in their seventh season. And ones I really like watching. But—it’s all still true.

Do TV shows actually “jump the shark” anymore? The phrase—originally conceived in the climactic moment when a leather-jacket-and-swimtrunk-clad Fonzie literally jumps over a shark in the Season Five premiere of Happy Days—refers to a TV show that’s passed its prime.

Since then, the idiom has been applied to everything from politics to commercial brands. But a recent 60 Minutes/Vanity Fair poll found that 83% of Americans today don’t know what “jump the shark” means—and another 9% thought the phrase itself had jumped the shark.

But whatever term you want to use, you know it when your favorite TV comedy is hitting its limit. It’s that moment you find yourself watching in stony silence. Or when every joke elicits, at best, only a weak chuckle. Or when, while watching the show, you’re wondering whether you have enough underwear to last you through the weekend. And then it’s time to face to the cold, hard truth: you need to give your favorite show the boot.

You’re still not sure? You just know that show has one more really good season in it, if only you keep your faith? Think again. Here are four signs your favorite show is in decline:

1. Peripheral characters take center stage

A hit TV show works for a reason: the stories revolve around its main character. When side characters start to edge out the protagonist, the show starts to feel unfocused. Like when The Simpsons began to feature every character—Krusty (in “Insane Clown Poppy”), Mr. Burns (in “A Hunka Hunka Burns in Love”)—except those who were part of the show’s namesake family. Or when South Park episodes began centering on Randy or Towelie (think: “More Crap,” “Over Logging,” “Margaritaville,” and “A Million Little Fibers”). Or in later episodes of Scrubs, when supporting characters, including Dr. Cox and Turk, began replacing JD as the narrator.

Supporting characters are just that—supporting—for a reason: they aren’t fleshed out enough to carry an entire episode. The protagonist is the character the audience knows best. When a show starts focusing on another character that the audience isn’t emotionally invested in, it can’t help but struggle to keep viewers interested.

2. The premise changes

Scrubs fundamentally changed in Season Nine when the setting switched from Sacred Heart Hospital to medical school. The show was no longer about a fresh group of doctors adjusting to the emotional ups and downs of life in the hospital. Instead, episodes focused on the struggles of a whole new crop of students—whom the audience barely knew. Viewers missed out on the emotional payoff of watching characters evolve over eight seasons.

In TV, familiarity breeds comfort. With the switch, Scrubs Season Nine was essentially a new show, competing against every new pilot that debuted that fall—but with one major disadvantage: Scrubs already had an audience, and it was an audience with high expectations and a low tolerance for change.

3. Writing staff or actors leave

Writing staff, producers, and directors shape the tone and style of a show in a pretty major way—more, even, than the actors on-screen. And if the off-screen talent leaves, you’ll notice. When Larry David left Seinfeld, the show lost the voice of its head writer who had dictated its style and sense of humor for seven seasons. When Steve Carrell left The Office, his departure cost the show not only its main character, but one of its writers, producers, and key creative voices.

Of course, actors matter too: Who can forget when Daphne Maxwell Reid inexplicably replaced Janet Hubert-Whitten as Vivian Banks on The Fresh Prince of Bel-Air? (Although, to be fair, no amount of backstory would have been able to explain that one away.) A change in the comedic style or dynamic of a TV show makes the experience unfamiliar—and therefore often unsatisfying—for the audience.

4. It relies on too many topical parodies or pop culture

When it comes to overuse of pop culture ploys, The Simpsons and South Park are the most obvious culprits. The problem is that topical parodies generally don’t have enough substance to support an entire episode. Pop culture jokes or random celebrity guest stars result in cheap one-time laughs, but that’s hardly enough to generate twenty minutes of material. Plus, both devices detract from the emotional core of a TV show—the conflict and resolution of a relatable protagonist.

After a show has been on the air long enough, the writing staff will eventually run out of ideas. It just happens. If your favorite TV show is guilty of any of the above, bad news: it’s probably time to consider the shark jumped. Reset your DVR, and find a new cast of characters to love.

Photo courtesy of Wonderlane.