The 72 million American baby boomers, born between 1946 and 1964, are turning 65 at the rate of roughly 10,000 a day, and many are considering not just how to age (with or without annuities? soy sauce? crow’s feet?), but also where. Wid Chapman, an architect, and Jeffrey P. Rosenfeld, a gerontologist who specializes in the relationship between aging and the built environment, collected 33 examples of residences that have been recently designed to bridge the distance between one’s vital and declining years.