Retirees recently found out their annual cost-of-living adjustment for Social Security in 2025, and now it's time to enroll for Medicare. Similar to Social Security, the Medicare program has many rules and can be complex.

Major changes in 2025 include Medicare Advantage plans and a new $2,000 out-of-pocket max under Part D, eliminating "donut hole" coverage gap.

Open enrollment for Medicare runs from Oct. 15 to Dec. 7 every year. The AARP recommends comparing plans, signing up at the right time, and fully understanding your options when enrolling, so your health and wallet don't take a big hit.

When you retire, it’s important to understand how Medicare works and how you can get the best and most cost-effective coverage. Many retirees wonder how to determine whether they need all four parts of Medicare.