Two years ago, Matt Jackson returned to New York for work. After 14 years in Dallas, he was unprepared for the high rents, small spaces and quick turnaround. “Apartments turn over within hours,” he said.

So he landed on Roosevelt Island, because a place there was available, affordable and large enough to fit his furniture. His one-bedroom at the Octagon, at the north end of the island, rented for around $2,500 a month.

Mr. Jackson, who grew up in Westchester, had an uneventful first year there. He teaches American history at a school on the Upper East Side, and when he returned home from work, he generally ate dinner and Skyped or Facetimed with his fiancée, Angela Putman, who was working on her Ph.D. in communication at the University of New Mexico.

When Ms. Putman, 39, joined Mr. Jackson, 46, last summer, they stuffed two lifetimes into the one-bedroom. Some of it was memorabilia, “not stuff you display or use,” Ms. Putman said. “It stays in bins.” They soon upgraded to a $3,550 two-bedroom at the Octagon, with those bins lining a wall in the second bedroom.