The answer to this question, depends on the specific details of your situation.

If you (or your spouse) currently work for an employer, and you have creditable health insurance that is not a High Deductible Health Plan (HDHP), enrolling in Medicare Part A may be a good option. As you approach retirement you can transition to the Medicare plan options of your choice.

However, if you do not have creditable coverage through an employer you will want to enroll in a Traditional Medicare (Parts A, B, & D and perhaps a Medigap Plan) or a Medicare Advantage Plan. If you do not have creditable coverage and do not enroll you are subject to financial penalties.

The points below and fact sheet link are resources to help you determine what will work best for you.

Key Points in Deciding Whether to Enroll  

• If you have creditable health insurance (typically, what you have through an employer with > 20 employees) you can delay Medicare and you will not pay a penalty. (Check with your employer or your spouse’s employer.)
• If you have creditable insurance, you can enroll in just Medicare Part A (Hospital Insurance), unless you have a High Deductible Health Plan.
• If you have a High Deductible Health Plan, generally, you cannot have other health insurance. Find out more in IRS Publication 969 at irs.gov
• If you have a Health Savings Account, you want to stop contributions 6 months before enrolling in Medicare.
• If you have creditable health insurance, delaying Medicare may save you money. Even Medicare Advantage Plans that promote a $0 premium, often take money directly from your Social Security retirement benefits.
• Medicare Part A (Hospital Insurance only) premiums are $0. (As long as you or your spouse have paid 10 years of Medicare taxes.)
• If you start receiving Social Security benefits you are automatically enrolled in Medicare Part A, Hospital Insurance. If you have creditable health insurance, you can opt-out of the other parts of Medicare without penalty.
• As you transition to retirement, and out of employer creditable health insurance, you are eligible for a Medicare Special Enrollment Period. Enroll within this time frame and to avoid penalties.

Find out more “Fact Sheet: Deciding Whether to Enroll in Medicare Part A and Part B When You Turn 65” https://www.cms.gov/Outreach-and-Education/Find-Your-Provider-Type/Employers-and-Unions/FS3-Enroll-in-Part-A-and-B.pdf

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