In just 12 years, the oldest members of the huge baby-boom generation will turn 80. Many will need some kind of long-term care. A new study from AARP says that care could vary dramatically in cost and quality depending on where they live. The study was motivated by a simple fact: The number of available family caregivers is declining. In 2010, there were potentially seven for each person 80 years old or older. By the time baby boomers reach that age, there will be only four potential caregivers for each of them. And those numbers are expected to continue declining. Chalk it up to longer lives and smaller families.