The answer is yes if you are going to retire and not be covered by an employer group health plan. If you are self-employed and have an individual health insurance plan, you will need to enroll in Medicare.
The answer is no if you are going to continue to work and get your health insurance from your employer or if you are covered by your spouse’s employer group health plan. If your employer has fewer than 20 employees and you continue to work once you turn 65, you may have to enroll in Medicare. My advice is to always check with your employer before making your final decision about whether to sign up for Medicare once you turn 65.
I always advise people who are going to get their health insurance from their employer after they become eligible for Medicare only to enroll in Part A of Medicare because it is free. Part B of Medicare cost $135.50 per month and could cost more depending on your income if your annual income is more than $85,000 single or $170,000 married. If your employer has more than 20 employees, your employer plan will be your primary insurance, not Medicare. You can enroll in Part B of Medicare after you retire and come off of your employer group health plan without having to pay a late enrollment penalty.
Enrolling in Medicare even though you are still working can make sense for some people. If your employer plan has a high deductible and your out-of-pocket costs are high, you may want to go ahead and enroll in both Part A and B of Medicare and drop your employer plan. If you did that you would need to select a Medicare Supplement and a Part D prescription drug plan.