Liz Weston

About 1 in 3 people 65 and older in the U.S. enroll in Medicare Advantage, the private insurance alternative to traditional Medicare. It’s not hard to see why: Medicare Advantage plans often cover stuff that Medicare doesn’t, and most people don’t pay extra for it.

But Medicare Advantage can be more expensive if you get sick because copays and other costs can be higher, says Katy Votava, president of Goodcare.com, a health care consultant for financial advisors and consumers.

Unhappy customers who want to switch back to traditional Medicare may find they no longer qualify for the supplemental policies to help pay their medical bills, or that they would face prohibitively high premiums.

“These are complicated products,” says Votava, author of “Making the Most of Medicare.” “They’re like nothing else, no other insurance that people encounter anywhere until they get to Medicare.”

In my latest for the Associated Press, making sense of the Medicare alphabet soup.