Russ Chung once lived in a sizable Midwest home, but he recently downsized to a luxury one-bedroom rental in Midtown Manhattan just blocks from Central Park.
Now, rather than mowing a lawn, the 60-year-old higher education administrator spends his free time visiting museums and taking in New York's other cultural offerings.
"As you get older, there are only so many things you want to concentrate on. Apartment life lets you focus on things that matter and get rid of stuff that takes up a lot of time," said Chung. His building's concierge signs for his packages, and arranges for housecleaning.
Chung is one example of a subset of baby boomers who have become the fastest-growing group of renters across the nation. Since they tend to have more money to spend than their millennial counterparts, developers are actively figuring out how to lure them to into one of the luxury buildings sprouting up across the city.
Both boomers and millennials are flocking to areas like downtown Brooklyn, where a flurry of new full-services high-rises are springing up — and they sometimes compete over units, Citi Habitats agent Jason Burke told CNBC.
According to Burke, even though there is a glut of these new apartments, there is only a limited number in certain price ranges. Most people want to get in first when the developers are offering the best discounts, he said.
"The boomers are the biggest demographic that can afford it," he said. "But tech levels everything. We're seeing a lot of engineers come to New York, a lot of people in tech who don't work from an office."
Between 2009 and 2015, the number of renters aged 55 or above rose 28 percent, while those aged 34 or younger only increased 3 percent, according to Census data recently crunched by search engine RentCafe.
Meanwhile, more than 5 million baby boomers across the nation are expected to rent their next home by 2020, according to a 2016 analysis from Freddie Mac. Some boomers want to stay close to the neighborhoods they have lived in for decades; others are following their children to cities, experts said.
Like millennials, many boomers want amenity-rich apartments in good neighborhoods.
"You would think they would be buying and investing in property, but a lot of people like the convenience and ease of renting," said Phillip Salem, an agent at real estate brokerage firm Triplemint.
"A lot of millennials are moving into brand-new rentals, and a lot of boomers are saying 'That's what's I like too,'" he added.
Salem's own Manhattan high-rise — with a gym, yoga studio and three outdoor lounges — is comprised of about 70 percent millennials and 30 percent baby boomers, the 30-year-old estimated.
"When I'm on the roof deck grilling, there are a lot of baby boomers," Salem said. "They come and sit with us. We chill. It's a community."
Chris Bledsoe, co-founder of the national co-living brand Ollie, told CNBC that boomers account for one out of every four email inquiries.
Ollie offers an all-inclusive living experience in micro-unit studio apartments (under 400 square feet), or micro-suites where renters have private bedrooms while sharing kitchens, bathrooms and other common spaces. Roughly 80 percent of tenants in Ollie buildings are in their 20s and 30s, but just under 20 percent are over the age of 50 — and about a third of those are in their 60s, Bledsoe said.
In fact, Ollie renters only need to bring their toothbrushes. The units come with modern multipurpose furniture to make the most of small living spaces. A butler service called Hello Alfred sends home managers to pay weekly visits to water plants and make beds, while each building organizes social events like ski trips, whitewater river rafting and guacamole-making contests.
"I say millennial is a mindset not an age group," he said. "Boomers are seeking something urban. They want cultural vibrancy, the theater. They want to be close to where their kids and grandkids are."
Zach Ehrlich, of New York-based brokerage Mdrn. Residential, recently launched a concierge-like rental service called Stoop that offers short-term leases. It's attracting interest among boomers looking for a "hands-free lifestyle" and to sample living in new places.
"There are a lot of seniors finding they want to have more flexibility," Ehrlich said. "They also want to have some sociability, whether they lost a spouse or are separated or just don't have a family unit."
Wendy Sanders, a Long Island, New York-based broker with Douglas Elliman, said that downsizing boomers often sacrifice space to live in something that's brand new.
"They're looking for maintenance-free living. When the toilet overflows, they want someone to take care of it," she said.
For Chung, whose job brought him to New York this spring while his wife spends more of her time in their 2,500-square-foot home in Ohio, it is important that he feels well cared for — yet not part of a senior residence, he said.
"As I'm getting older I'm stressed about this: If I fall down and hurt myself here, what do I need to do?" said Chung. "Why am I even worried? I'm going to pick up the phone and call the front desk. I just have to get to the phone."