The rules for mammograms are simple: You either get yours once a year, every other year, or not until the age of 45. Or 30. Maybe wait until 55? Or never? Go every two years after the age of 50, or every year...Or start young, because you can never be too careful.

See? Simple. The American Cancer Society revised its mammogram guidelines this week, suggesting that most women should start at the age of 45. The previous guidelines said women should get one every other year, starting at the age of 40. This conflicts with what some other groups have suggested, which complicates things for women looking for a simple answer.

Medical ethicist Art Caplan joined Jim Braude and Margery Eagan on Boston Public Radio to reveal the simple answer, or at least admit that there isn’t one. “It’s not ‘one size fits all,’" Caplan said. “It really is important that you personalize the testing pattern and really go over that with a doctor.”

According to Caplan, the most aggressive forms of cancer most commonly occur in women younger than 45. So how does not having a mammogram until middle age help? “Those tend to be the ones that are genetically based and early onset,” he said. “If you have a history of breast cancer in your family, if you got tested and knew that you had a gene that was at high risk for developing breast cancer, you don’t want to follow the general rules, you want to screened earlier and more often.”

When it comes to medical professionals, most doctors will opt with more mammograms, rather than fewer. Caplan said this is more of a liability issue than anything else. “The safest thing in some ways is to just say start very early and get them every year,” he said. “[That way] we won’t miss anything and you won’t be mad at me if somehow we didn’t do that, and something was discovered later.”

At the same time, Caplan said there’s a reason why the American Cancer Society has pushed the age up—the risks can often outweigh the benefits. “It doesn’t seem to make a difference to mortality that much," Caplan said. “You get exposed to a lot of unnecessary radiation, there are a ton of false positives, so you’re chasing down cysts and other things that have nothing to do with cancer.”

Ultimately, the main rule is to do what works for you, as an individual. “In general, the ‘over 45’ rule is good," Caplan said. “That said, if you have a history of breast cancer in your family, if you got tested and knew that you had a gene that was at high risk for developing breast cancer, you don’t want to follow the general rules, you want to screened earlier and more often. I do think you need to talk to your doctor, provide a family history, and talk about your lifestyle and your health. That shifts your risk factor, and you may want to get screened more often.

Medical Ethicist Art Caplan heads the Division of Medical Ethics at NYU’s Langone Medical Center, and co-host of theEveryday Ethics podcast. To hear more from his interview, click on the audio links above.