Planning well in advance of your Medicare eligibility can help you get every dollar in Medicare benefits you have coming to you. Here, in a nutshell, is what you should do and when you should do it.

12-6 months before your 65th birthday
Set up your post-retirement budget. Talk to someone about your retirement financial goals and make a list of your expenses or financial obligations.
Meet with your employee benefits department or call your existing health plan to learn about plan options available to you after retirement.
Review your Social Security statement to be sure your stated income is correct.
Decide when you want to start receiving your Social Security benefits and be sure you understand how it will affect the monthly benefit payments you will receive. Compute the effect of early or delayed retirement.
5-4 months before your 65th birthday
Take time to read up on the parts of Medicare.
Confirm your eligibility for Medicare benefits.
Explore our plans’ different networks and drug lists (formularies). Find out if your doctor, hospital, and pharmacy are in network and if your prescription drugs are covered. It’s good to know this now, so you can choose the right plan later.
3-0 months before your 65th birthday
Enroll in Medicare Parts A and B by contacting the Social Security Administration at www.socialsecurity.gov or 1-800-772-1213 (TTY: 1-800-325-0778).
Review your plan options and decide whether you want to select a Medicare Advantage (Part C) plan with or without Part D prescription drug coverage, a Medicare supplement (Medigap) health plan, or a Part D plan.
Call us at 1-877-393-6733 (TTY/TDD: 711) 8 a.m. to 8 p.m., 7 days a week, to answer any further questions you may have regarding your coverage options.
Meet with a licensed agent to apply for a plan in person.
On your 65th birthday

Relax and enjoy it. If you have followed the steps outlined above, you will have all the coverage you want in place to Retire with Independence.

https://www.ibx.com/medicare/find-a-medicare-plan/medicare-basics/turning-65-checklist