Start with your timeline
Your enrollment timing depends on why you are becoming eligible and whether you have current coverage through work or another source.
Review current coverage
Before making changes, understand whether your employer or other coverage is considered For Part D, coverage Medicare treats as at least as good as standard drug coverage. That can let you delay Part D without a late penalty. Part B delay depends on group coverage from current work. Get either answer in writing. and how it coordinates with Medicare.
Build the coverage picture
After Parts A and B, evaluate prescription coverage and whether Medicare Advantage or Original Medicare with a Medicare Supplement (also called Medigap) better matches the factors you care about.