Shore has listed that house for $25 million. “It used to be that you had to build a really great kitchen,” she says. “You still do, but you also have to build a really great master.”

“I’m thinking living rooms are the opposite of what they’re called, because no one lives in them anymore,” she continues. “People build cozy dens off the kitchen or master bedroom, because that’s where everyone gathers, while the living room collects dust.”

A Lifestyle Choice
This isn’t the first time giant master bedrooms have been in vogue: A $4.65 million house in Boca Raton, Fla., built in the late 1980s, has a master suite that includes a bedroom, bathroom, office, family room, bar, and gym—but brokers say it’s only recently that buyers have begun to specify that master suites resemble stand-alone apartments.

Today, people spending more than $10 million for a house want “things like wet bars, drawing rooms, dressing rooms, and oversized bathrooms” in master suites, Graves says. “Before,” he says, people wouldn’t really expect those things.”

“It’s very lifestyle-driven,” says Tim Davis, a broker for Corcoran who’s based in New York’s Hamptons. “It’s a very European way of living, where they’re shutting off part of the house.”

Davis, who renovated his own home to create a master suite after his children left for college (“It enables us to have this separate apartment that’s self-contained”), says many of the luxury homebuyers in the Hamptons “haven’t grown up with wealth, and some don’t know how to live that way.”

When they see giant master suites at hotels or “spend enormous amounts of money renting villas or resorts, they’ve figured out that’s how people want to live, and they say: “Why can’t I do that and spoil myself?” Davis says.

Developers, he says, have taken note. “We advise our developer clients [who are building homes on spec] to build the master suite on the first floor,” he says. “Or, if it’s on the second floor, then they should make sure there’s an elevator that goes to the space.” One $39.5 million new home in Southampton, N.Y., which Davis co-lists with broker Gary DePersia, has just that: a master suite with a sitting room and two bathrooms, which can be accessed by elevator.

It’s not just to accommodate an aging, wealthy buyer pool, Davis explains; it might just be about “getting luggage into closets.”

Hard to Let Go
There’s a certain irony to the fact that baby boomers in giant houses have begun living in suites the size of a starter apartment in Brooklyn. It’s doubled by the fact that this is almost exclusively a feature used by the very wealthy.