Many Americans are worried about the healthcare expenses they're facing now, or ones they may face in the future. Medicare coverage is a huge help to many -- more than 50 million enrollees recently, to be specific. If you're a Baby Boomer with Medicare around the corner, there's a lot you need to understand about it. Here are nine important things to know.

It's important to enroll on time Enrollment in Medicare is automatic for some people (those who are already receiving Social Security benefits at age 65), but not for all. Enrolling on time matters a lot, because those who enroll late risk having to pay more for it for the rest of their lives -- as some of the premiums may rise by 10% for each year that you were eligible for Medicare but didn't enroll.