Turning 65? Start Here.

The best time is the 3 months before your birth month (the first 3 months of your Initial Enrollment Period). Enrolling early means your Part B coverage starts on the 1st of your birthday month. If you wait until your birthday month, coverage starts the 1st of the following month. Waiting longer delays coverage further and can expose you to the late enrollment penalty.

The IEP is a 7-month window centered on your 65th birthday. It starts 3 months before the month you turn 65, includes your birthday month, and extends 3 months after. During this window, you can sign up for Medicare without a late enrollment penalty. Missing it can result in a lifetime premium surcharge of 10% for every 12 months without creditable coverage.

Medigap Open Enrollment (OEP) is a 6-month period that starts when you're both 65 and enrolled in Part B. During this window, insurance companies cannot deny you a Medigap policy or charge you more based on pre-existing health conditions. After this window, you may be subject to medical underwriting — meaning insurers can charge more or deny coverage. This is a one-time opportunity.

If you or your spouse have "creditable coverage" through a current employer with 20+ employees, you may delay Medicare Part B and Part D without penalty. You'll have a Special Enrollment Period (SEP) to sign up when you leave that employer coverage. Important: Get a "Notice of Creditable Coverage" letter from your employer to protect yourself from the LEP. Retiree coverage or COBRA does NOT count as creditable coverage for purposes of delaying Medicare.

If you don't sign up for Part B when you're first eligible (and don't have creditable coverage), your monthly premium will permanently increase by 10% for each full 12-month period you were eligible but didn't enroll. For example, going 24 months without Part B coverage adds a 20% surcharge to your Part B premium — for as long as you have Medicare. As of 2025, the base Part B premium is $185/month. A 20% penalty adds $37/month permanently.

Original Medicare (Parts A + B) + Medigap supplement gives you nationwide coverage — see any doctor who accepts Medicare, no referrals. Medigap covers most out-of-pocket gaps. Higher monthly premiums but highly predictable total costs. Good if you travel, have chronic conditions, or value freedom.

Medicare Advantage (Part C) bundles Parts A + B (and usually D) through a private insurer. Usually lower premiums, often includes dental/vision/hearing. But uses provider networks (HMO/PPO), may require referrals, and has annual out-of-pocket maximums up to $8,850 (2025). Better for healthy people who want simplicity.