Once, turning 65 typically meant retirement, Medicare and the inevitable onset of physical decline. It also often signaled the need to search for a geriatrician, a doctor who specializes in caring for the complex medical problems of the elderly.

But many of today’s older Americans are healthy, vigorous and mentally sound, with no urgent need to change doctors. They aren’t afflicted with age-related diseases or functional impairments. This raises interesting questions about when — and whether — those 65 and older need to make that switch.

Seeing a geriatrician “should never be age specific,” says Nir Barzilai, a longevity researcher at the Albert Einstein College of Medicine. “Biological age and chronological age are not the same. Asking what age to start seeing a geriatrician is not the right question. The right questions are: What conditions do you have? Are you mobile? Are you starting to get frail? Are you losing weight, or not walking well? Can you shop? Can you get to your apartment? Can you live by yourself?”

Ula Hwang, healthy and 47, already has answered those questions for herself. She has chosen a doctor who devotes much but not all of her practice to the elderly and expects to grow old under her care. Hwang’s mother, 76, also is her patient.

“I like her comprehensive view about health, medical care and the quality of life,” says Hwang, an emergency medicine researcher at Mount Sinai Hospital in New York. “I don’t want to have to switch later on. Why wait until I’m frail? I’d rather have someone who will know me a long time.”

For those who are frail and have multiple health conditions requiring many medications, a geriatrician might be the best choice, says Laurie Jacobs, a geriatrician and president of the American Geriatrics Society. “They probably need someone to organize all their care,” she says. “If someone has troubles functionally or cognitively, a neurologist can evaluate, but doesn’t take care of you.

“Geriatricians are patient centered,” adds Jacobs, who also chairs the department of internal medicine at Hackensack University Medical Center in New Jersey. “They are internists on steroids — they know about medical problems, but know a lot more about people. They are good listeners, and involved with the whole person.”

If you are looking for a geriatrician, however, you might have trouble finding one. There is a nationwide shortage. Only 6,910 certified geriatricians exist in the United States, including 3,590 full-time practicing geriatricians, according to the geriatrics society. Certified means they have undergone at least one fellowship year of specialty training beyond their primary care practice, with the option of two additional years of geriatric-focused research.

But keep in mind that many primary care physicians — such as Hwang’s — lack certification but still have considerable experience treating geriatric patients. Many doctors shy away from full-time geriatrics because it typically pays less than other specialties. “Fellowship-trained geriatricians are a dying species,” Hwang says. “Many fellowship spots go open every year because the payment incentives to become a geriatrician are so low. You get paid more as an internist right out of residency than you would be paid if you did one or two years of additional training to become a geriatrician.”

To encourage more primary care physicians to move into geriatrics, the National Institute on Aging (NIA) has targeted specific research grants for them to “get their feet wet, and design a professional career plan that will create a niche for geriatrics,” says Susan Zieman, a medical officer in NIA’s geriatrics division. The program, called Gemsstar, is research oriented — the institute can fund only research — but the goal is to get primary care doctors excited about geriatric care and better equip them to deliver it, she says.

While salaries and Medicare reimbursements are low and the public perception is that “aging isn’t very sexy in our society,” Jacobs says geriatricians are among the most satisfied of clinicians. “They feel they are doing important work, and they are happy,” she says. “Those of us in the field love talking to older people, and find them very enjoyable to take care of.

“Many of our patients have led very interesting lives, and we love hearing their life stories,” she adds. “Still, geriatrics is a hard sell, since most physicians want to do something high tech or cure people. But I think it’s a great field, and I’m very dedicated to promoting it.”

Jacobs also treats patients younger than 65.

“I have a lot of older, frail patients, but I also have some who are younger and fit who know they will have me on their side when they become old and frail,” she says. “I call them my ‘pediatric’ patients. I’ve had some patients for 25 years. I don’t think the public knows this. People think it’s just end-of-life care. I’ve had a couple of patients whose children waited until they were old enough to also become my patients.”

Thus, there really is no firm time or age to make a switch — that is, if you can find geriatricians who will have room in their practice to take you. To be sure, some conditions require a deeper dive that a geriatrician in particular can provide, such as dementia, frailty and mobility problems. On the other hand, if you have a primary care physician comfortable handling geriatric patients, you may want to stay put. It’s a decision that should be made based on individual circumstances.

“Geriatricians learn a lot of neurology and psychology because our patients tend to have a lot of neurologic disease who also need primary care,” Jacobs says. “A specialist can make the diagnosis, but can’t help you navigate your life, which is what geriatricians do. Their aim is to keep you as independent as possible. Deciding to move to a geriatrician should be when patients aren’t getting what they need from their current care providers — and that could be at any age.”