The lifespan of a cup of coffee epitomizes Judd Apatow’s “This Is 40.” First, it’s too hot: overambitious, hit-or-miss humor nested in Viagra jokes and incredible spouse dynamics. Next, it’s just right: Strong performances emerge and the title validates. Last, after sitting paralyzed for two hours, it’s a cool stool sample: Drawn-out sequences get lost in a scrawling script that begs for sympathy. The laughs are there but devoid of variety and form.

Apatow is a predictable filmmaker. Not unlike Dane Cook — the Ryan Reynolds of standup — Apatow makes self-respecting funnies angled for a millennial audience. Biggest concern? Longevity. His stamina will continue to be challenged. But guess what: “Predictable” can be a good thing. You know what you ordered when one of his films open. “This Is 40” is no exception. With recycled actors and congruent plot frameworks, his semi-sequel scores through the uprights, but never quite reaches the end zone.

Congratulate Pete and Debbie (played by Paul Rudd and Leslie Mann, “Knocked Up”). Unsurprisingly, they are approaching the 40-year mark. In Debbie’s mind, she’s turning 38 again, not 40. This is further backed during a scene at the gynecologist when two nurses inquire why her birth year climbs higher each visit. Pete, however, remains honest to his Tour de France biking club jerseys and his covert cupcake fetish. They loosely make a pact to exercise daily, revamp diets and rectify relationships with their respective fathers (Albert Brooks, “Broadcast News,” and John Lithgow, “The Campaign”). We follow the pair as they fight, rekindle, jest and fume.

Professionally, Rudd operates a suffocating record label while Mann manages a clothier that’s missing an unexplained $12,000. Supporting, Chris O’Dowd and Megan Fox add pizzazz and mountainous cleavage (respectively) as coworkers. Even Jason Segel, an Apatow veteran, is thrown in the mix as the prescient, womanizing personal trainer. Fox’s character brainlessly answers, “I’m just young,” as Debbie cops a feel of her supple juggies.

Several elements work in “This Is 40.” Primarily, the film tackles precisely what its title suggests: oncoming menopausal behavior, overprotective guardians, receding hairlines and Generation Y-technology cluelessness. In this sense, the film’s grounded reality and honesty appear refreshing. In the past, Apatow has excelled in depicting life’s inevitable encounters that people pretend don’t exist. You have everything from the graying virgin to a comic’s misery.

Mann kills while Rudd weakly follows. To be fair, Debbie is structured stronger than Pete, but we fail to sympathize for Pete the way Apatow hopes. His crippled business marries with his inability to refuse his broke father monthly checks. Ideally, you want to pat weaker characters on the back and ensure them it’s going to be OK. That never happens.

“This Is 40” pigeonholes itself as an older person movie. Unless younger viewers have parents with overlapping traits and empathies, it’s tough to resonate. With an overlong runtime, the film eventually feels like it’s working on fumes, and many unnecessary scenes bog down the script’s momentum.

Thankfully, though, Apatow specializes in one important category: handcrafting a unique, relevant perspective on harmlessly contentious subject matter …

In this case, it’s enduring the discovery of gray pubes.