Guide
Turning 65: the Medicare playbook
The year around 65 in order: what to do seven months out, when your enrollment window opens, how to choose a path, and what to expect in your first months.
Medicare at 65 is a sequence of small decisions with fixed dates, not one big decision. Done in order, none of them is hard. Done out of order, a few of them cost money for the rest of your life. Start with step 1, seven months before your birthday.
The year, in order
Step 1 · Seven months before your birthday
Learn what each part of Medicare does
Part A is the hospital. Part B is the doctor. Part C is a private plan that bundles A and B. Part D is the pharmacy. Every later decision uses this vocabulary, so learn it before the mail starts arriving.

Step 2 · Six months before
Decide what happens to your work coverage
If you or your spouse will keep working past 65 with coverage from a larger employer, you may be able to delay Part B without a penalty. If the employer is small, or the coverage is COBRA or a retiree plan, you usually cannot. COBRA is the job coverage you can keep paying for after work ends.
Settle this first, because it changes every date below.

Step 3 · Three months before — your window opens
Know your Initial Enrollment Period
Your first window runs seven months: the three before your birthday month, the month itself, and the three after. Enrolling in the first three means coverage starts the month you turn 65; enrolling later delays it. Put the dates on a calendar now.

Step 4 · Three months before
Choose your path
You choose between two paths. Original Medicare with Medigap — a private policy that pays what Medicare leaves — lets you use any doctor who takes Medicare, with predictable costs and a higher monthly premium. Medicare Advantage bundles your coverage into one private plan with a lower premium and extras, but a network and approval rules. A network is the plan's own list of doctors and hospitals.
Moving from Advantage to Medigap later is much harder than the reverse, so decide it with the comparison, not the commercial.

Step 5 · Two months before
Cover your prescriptions
Part D is separate unless your Advantage plan includes it. Compare plans on the drugs you actually take, at the pharmacy you actually use — and enroll even if you take nothing today, because the penalty for waiting is permanent.

Step 6 · Two months before
Know the costs and the help available
Part B has a monthly premium that rises with income; Part D plans and Medigap add their own; each part has cost-sharing. Cost-sharing is the share of each bill you pay yourself. Extra Help and Medicare Savings Programs cover some of it for people with limited income.
Run the numbers for your situation before you commit.

Step 7 · Your birthday month
Sign up
If you already receive Social Security, Parts A and B arrive automatically; if not, you apply through Social Security yourself. Advantage, Part D and Medigap are each a separate enrollment with the plan. Keep every confirmation.

Step 8 · Your first months on Medicare
Settle in and avoid the expensive mistakes
Cards arrive, the first bills arrive, and the fall enrollment period comes around faster than you expect. Check that every provider you use is in network or accepts Medicare, set up premium payments, and note the dates you can change plans if the first choice was wrong.

The mistakes that are hard to undo

Assuming employer coverage, COBRA or a retiree plan lets you skip Part B. Only current employment at a larger employer does, and the rules are specific.
Waiting for a letter. If you are not already receiving Social Security, nobody enrolls you — you start the application yourself.
Choosing a plan by its premium alone. A low monthly cost buys a network and approval rules; whether that trade is right for you depends on how you use care.
Skipping drug coverage because you take nothing today. The late-enrollment penalty is permanent and grows every month you wait.
Missing the Medigap open-enrollment window, the six months after your Part B starts. In most states it is the one time a Medigap insurer cannot ask about your health.
Where to go from here
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