If you haven’t yet experienced the waggish majesty that is 30 Rock, you have some time to catch up -- but not a whole lot. Tina Fey’s first sitcom stands among the best shows of the 21st century, but it also has one of the fastest expiration dates for a non-news series. To be appreciated in full, it’s gotta be seen — well, what are you doing after reading this article?

30 Rock debuted only a decade ago, but the show’s often topical sense of humor -- which Fey honed during her long tenure at SNL -- means that a sizable minority of its references are currently drifting away into obsolescence. During the show’s run, the timeliness of the jokes underscored the sharpness of its observations and the freshness of its characters. In retrospect, Fey’s Liz Lemon -- with her tackling of issues like female leadership, microaggressive sexism, and the lofty-yet-dirt-common goal of “having it all" -- heralded a new era of TV in which female characters explicitly discuss their feminism on shows as diverse as Scandal, Girls, Broad City, UnReal, Crazy Ex-Girlfriend, Parks and Recreation, and Orange Is the New Black.

But 30 Rock’s contemporaneity has proved a double-edged sword. “Cooter,” the Season 2 finale, is one of the most brilliant installments the show’s ever produced, with NBC chief Jack Donaghy (Alec Baldwin) defecting to the Bush administration once he realizes that he’ll never attain his dream job as GE's CEO. But it’s also an episode in need of footnotes today, especially for younger viewers who may not remember Dubya’s fratty penchant for staff nicknames (hence “Cooter Burger,” guest star Matthew Broderick’s character) or why Washington was in desperate need of an Acting Head of FEMA. NBC is no longer owned by GE but by Comcast, an ownership transition dramatized by the series’s frequent meta-media commentary.

Other episodes allude to Brett Favre’s dick pic and NBC’s fractious replacement of Conan O’Brien with Jay Leno, both major news in 2010, and the final season includes a cameo by Ryan Lochte, the Olympian swimmer best known for not being Michael Phelps. And you’d have to have watched NBC during the summer of 2012 to understand Jack’s insistence that “It’s ‘We peacock comedy!’ You say the ‘peacock.’”

30 Rock isn’t alone in riffing on ephemera for laughs; pop culture and the news are wellsprings for Family Guy and South Park, as well as countless others. But unlike those other comedies, especially in their later years, 30 Rock is and has remained a Great Show. That’s in part because, despite her superficial similarities to other single gals in the big city, Liz Lemon is an original -- a grumpy, sex-phobic, fully clothed female nerd who pines for motherhood and night cheese much more fervently than she ever did a man. Her unlikely friendship with Jack -- another exceptional creation, burdened by paralyzing mommy issues and buoyed by a jagged snobbery that stems from growing up poor and emotionally neglected in Sadchester, Massachusetts -- will certainly stand the test of time.

Perhaps with so much content crowding all of our various screens, there’s little point in writing toward endurance. Unlike the film world, in which cinephiles are expected to know their Casablanca and Cassavetes, TV fanatics (and critics) tend to pay less attention to the medium’s history. But those of us who want to engage in one of art’s greatest pleasures -- sharing it with those we love -- are finding some of our favorite shows crumbling by the month. Unlike the self-contained universes of, say, Mad Men or Breaking Bad, 30 Rock needs to have been seen during its initial run for a viewer to fully feel the extent of its genius. It’s not too late -- for maybe a couple more years.

If Fey cares about 30 Rock’s short afterlife, she’s doing slightly better at shielding her new series, Unbreakable Kimmy Schmidt (Netflix), from the ravages of time. Many of the jokes, in fact, are grounded in the persistence of pop culture. After 15 years in a bunker, Ellie Kemper’s Kimmy is confused by technology like cell phones, but she’s right at home with Ninja Turtle birthday parties and (newly resurgent) Lisa Frank stationery. As movies and stars and scandals and presidents replace one another, memory will inevitably fail us. But, as Kimmy Schmidt seems to argue, nostalgia is forever.