Medicare is a federal health insurance program primarily for people 65 and older, although some younger individuals with disabilities also qualify. Think of it as having four main parts: Part A covers hospital stays, Part B covers doctor visits and outpatient care, Part C (Medicare Advantage) is an alternative way to get Medicare benefits through private plans, and Part D covers prescription drugs.

Most people don't pay premiums for Part A if they've worked and paid Medicare taxes, but Parts B and D do have monthly costs. Here's what catches many people off guard: Medicare doesn't cover everything. It has gaps in coverage, especially for long-term care, dental, and vision, so you may need private insurance to cover the difference.

Understanding these limitations before you need care helps you plan better and avoid unexpected expenses during what should be your golden years.