With the broadcast upfronts around the corner, the major networks are tasked with making crucial decisions regarding the fate of series new and old for the 2015-16 season.

Given the massive increase in the volume of primetime television shows, it’s tougher to decide whether to stick with reliable long-running programs or take a gamble on something new that could become a binge-worthy hit. Since viewers have more choices, networks may be less inclined to stick with older shows just for the sake of stability.

“In the platinum age of quality and choice, broadcasters have to be more aggressive about letting go of the past,” said producer and former NBC Entertainment president Warren Littlefield.

But viewers aren’t the only ones distracted by so many options. Actors are demonstrating a new willingness to bow out of successful series. Showrunners, in order to better shape a program’s long-term storytelling arc, also have been more proactive in setting limits on the number of seasons a series will run. Of course, that kind of planning is still a luxury in an environment where the failure rate remains above 80% for all new entrants.

“Grey’s Anatomy,” now in its 11th season, lost lead Patrick Dempsey, whose Dr. Derek Shepherd — better known as McDreamy — was killed on the April 23 episode of Shonda Rhimes’ medical drama. Before his sendoff, Dempsey had publicly spoken about leaving the show. ABC is sure to renew the sudser, which drew 11.6 million viewers this season, though Dempsey’s departure will necessitate new storylines and probably new characters to fill the void. “The possibilities for what may come are endless,” Rhimes said.

The trend of showrunners to limit a program’s life stems in part from the growth of serialized drama, which puts a premium on pacing and plotting the climax of major storylines. ABC’s “Lost” was a forerunner by necessity, given its intricate mythology.

Others are concerned about quality control in general. Lena Dunham, creator and star of “Girls,” has talked with HBO about completing six seasons of the half-hour dramedy. But she’s not certain she’ll go beyond that.

“I think America has a tendency to push shows past their due dates,” Dunham told Variety.

“Lost” alum Carlton Cuse recently revealed he doesn’t intend on continuing his FX horror series “The Strain” more than five seasons. Another HBO hit, “Game of Thrones,” may also be soon approaching its final days, despite its place as a pop-culture phenomenon and ratings juggernaut.

“We’ve got a very definitive idea of how much longer it is, and we’re getting there,” “Thrones” writer David Benioff recently told Variety. Though Benioff, along with writing partner D.B. Weiss, fully recognizes fans would flock to the series for years to come, he admitted, “The idea that we’re going to try and stretch it out by an extra couple years just because we’re all having a good time doing it and people are making money off it just feels like it would be a betrayal.”

The intensity of the competition across broadcast, cable and digital outlets is a key factor in determining whether or not to renew. “The landscape has changed, particularly with so much original content on the table,” said Littlefield, who earned an Emmy last year for FX’s “Fargo.” Calling the new shows smart and complex, he added: “They’re really appointment television. And by and large, they’re all going out to the same coveted 18-49 demographic.”

Littlefield sketched out the ways to measure success: audience levels and ratings, plus the creative potential left in the tank. There’s also an economic consideration. As shows get older, above-the-line costs grow significantly. “Hit shows are far more expensive than new shows,” Littlefield said. “In the past, there was a tendency to pay up as shows became more expensive to hold onto.”

For instance, “Castle,” now in its seventh season at ABC, is a solid performer that the net wants to keep on its slate, but it won’t happen without major tweaks on the call sheet. Series creator Andrew Marlowe is stepping away from season eight, as is David Amann, who replaced Marlowe this past year as showrunner. Meanwhile, star Nathan Fillion reached a deal for another season, but his co-star, Stana Katic, has yet to sign on again.

Littlefield noted a natural tendency among programmers to avoid risk if a show is still delivering respectable numbers. But he recalled his own decision to pass on ordering more episodes of “L.A. Law” after the legal drama completed its eighth season in 1994. NBC wound up filling the timeslot with “ER.”

“More than ever before, there needs to be something that truly merits (a show) holding on,” Littlefield said.

NBC handed an early-season-17 renewal to “Law & Order: SVU,” while CBS has yet to pick up “CSI” for season 16.

Yet network execs fretting over renewal/cancelation decisions can take heart in the safety net provided by another hot trend in TV programming: Pulling the plug on a well-loved franchise these days only starts the clock ticking on the opportunity to bring it back as an “event” series.