It's basically a rite of passage: You blow out the candles on your 65th birthday and get to sign up for Medicare.

Yet it's kind of like one of those birthday gifts that you have to assemble properly for it to work well.

In other words, if you enroll in Medicare without exploring the details of your medical coverage and weighing your options, you could end up on the hook for health care costs that you did not anticipate.

Every day, about 10,000 baby boomers reach age 65 and can join the 49 million or so other older Americans enrolled in Medicare. (The government program also provides coverage to about 9 million younger people with permanent disabilities.)