Two decades ago, then-NBC executive Jeff Zucker made headlines by “supersizing” “Friends” episodes as a monthlong stunt. But in the streaming era, viewers are frequently caught off guard by run times that vary considerably from one episode to another.

Freed from the need to fill a half-hour (actually, 21 minutes with commercials) or an hourlong (e.g., 44 minutes plus ads) time slot in linear TV, producers are allowing their shows to breathe — and let the story dictate how long or short an episode can be.

Netflix’s new Shonda Rhimes drama “Inventing Anna,” for instance, is an hour long … sometimes. Other episodes clock in at as many as 75 minutes, while the finale lasts a nearly movie-length 82 minutes. Disney Plus’ “The Book of Boba Fett,” meanwhile, varies anywhere between 39-minute episodes to a 61-minute finale.

“It’s just so strange that for my whole life, we were completely focused on” episode length, says Gareth Neame, executive producer of “The Gilded Age” on HBO, who performed similar duties on “Downton Abbey.” “The story had to fill a certain space. If you were really passionate, sometimes you could get another 30, 40 seconds, 60 seconds out of the broadcast because you just needed that extra space. And then suddenly, it’s fallen away as a major decider.”

So far in Season 1, “The Gilded Age” has fluctuated between more broadcast-style 46-minute episodes with longer 56-minute episodes (and an opening that clocked in at 80 minutes). Indeed, many hour-long episodes on streamers are just that — a full hour, which actually means a hefty 15 minutes more than your average drama on an ad-supported broadcast or cable channel.

Hacks” executive producers Lucia Aniello, Paul W. Downs and Jen Statsky note that when they worked on cable shows such as “Broad City,” they had to cut split seconds of their characters breathing to get their comedies to conform to the 21-minute limit.

Now, the added length “allows us to have room for stories that might have otherwise been really short,” Downs says. “We actually get to explore certain things that we otherwise might not.”

When “Evil” moved from CBS to Paramount Plus, executive producers Robert and Michelle King suddenly had more freedom to edit the show to the length they needed. “We have been able to take advantage of the running-time looseness,” Michelle King says. Adds Robert King: “We went back to Episode 1 and filled in some details of stuff that we cut because of length.”

Mega-sized episodes have long become the norm in reality TV, where two- and even three-hour episodes of shows like “The Bachelor” and “The Voice” are not uncommon. For show obsessives, that’s perhaps a good thing. But unscripted shows are obviously easier to digest and don’t require quite the same level of concentration as a lengthy scripted episode. And with so many programs to power through in the Peak TV era, having to sit through longer-than-usual episodes can be exhausting.

Even veteran showrunners note that there’s a different rhythm to TV versus the big screen — despite the moviemakers who insist they’re creating “long-form films” — and some of that comes from knowing your time limits.

“There’s one part of me that quite likes the discipline,” Neame says. “You know that every scene that stayed in the cut is something that really earns its place. Even if you’re bingeing something all the way through, we have a sense of how long an episode should last. If you start to go half an hour over, that feels a bit confusing. There’s a natural length to an episode that we’ve all been trained to watch.”

The irony in longer episodic lengths is that, as a whole, TV seasons are much shorter in the premium cable and streaming age. Beyond network procedurals and comedies, the days of 22-episode and 24-episode seasons are mostly a thing of the past, replaced by the 10, eight or even six-episode orders. That means that actually, even with these jumbo episodes, there’s a lot less of your average series to consume than there was a decade ago.

Coincidentally, the conversation about whether TV episodes are too long comes as there’s a general consensus in film that movies have pushed the limits with their run times. Those three-hour films? Why, that’s akin to a three- or four-episode limited TV series!

Ultimately, TV has entered an age of choice — not just for viewers, but for producers too. Want to tell your story in a traditional, 44-minute installment over the course of 22 episodes? Broadcast’s your thing. Interested in telling a shorter story in installments that can expand and contract like an accordion? Welcome to streaming.

Julie Plec, who is executive producing “The Endgame” for NBC, says she enjoys the freedom streaming brings viewers and creators — to a point. “But I don’t necessarily think that streaming needs to be an open invitation to just tell the story as long as you want to,” she says. “I don’t resent people who choose to then spend an hour and 20 minutes on an episode, as long as the episode itself feels like it’s strong in its intentions and it’s moving.”