The motives for relocating vary, of course. Ms. Cave, 67, moved to Riderwood because “I was the daughter who had to take care of parents from afar, and I swore I’d never do that to my kids,” she said.

At first, Ms. Cave recalled, “I looked around and saw the walkers and the scooters and thought, ‘My God, what have I done?’” Now, though, she appreciates the community college courses offered on campus, the square dancing and the pickleball, the shared meals. “The people are so interesting,” she added.

Such graduated communities allow residents to transfer to assisted living, nursing care or memory care units as their health declines. It’s a benefit that Carol Holmes Alpern, 81, learned to value after she and her husband, Bowen Alpern, moved into Foulkeways, a nonprofit Quaker-affiliated continuing care community in Gwynedd, Pa.

A healthy 68-year-old when he arrived in 2021, Mr. Alpern was diagnosed with a brain tumor the following year. When his wife could no longer care for him by herself, he entered hospice care in the Foulkeways nursing center, a short walk from the couple’s apartment. Having the option of 24-hour aides and unlimited visiting hours “probably saved my life,” Ms. Alpern said.

Her husband died last month, and now, “I can’t imagine leaving,” she said. Other residents “not only supported both of us, they cherished us.”