Aging into Medicare: What it means and how to prepare

What does “Aging into Medicare” mean?

“Aging into Medicare” refers to the process of becoming eligible for Medicare when you turn 65. For most people, this milestone marks an important transition in health care coverage. Understanding the steps and timelines ensures you avoid penalties and maintain continuous coverage.

Step 1: Know your eligibility

Most people qualify for Medicare at age 65 if:

• You're a U.S. citizen or permanent resident
• You’ve worked and paid Medicare taxes for at least 10 years (for premium-free Part A hospitalization insurance)

Step 2: Understand the enrollment periods

Initial Enrollment Period (IEP)

Your first chance to sign up for Medicare when you become eligible (usually at age 65).

• When: 7 months around your 65th birthday (3 months before, your birthday month, 3 months after)
• Why it matters: Enrolling during this time helps you avoid late penalties and coverage gaps

Annual Enrollment Period (AEP)

The yearly opportunity to review and change your Medicare coverage.

• When: Oct. 15 – Dec. 7 each year
• What you can do: Change your Medicare Advantage or Part D plans

Medicare Advantage Open Enrollment Period (MA OEP)

For people already enrolled in a Medicare Advantage plan who want to make a change.

• When: Jan. 1 – Mar. 31
• What you can do: Switch Medicare Advantage plans or return to Original Medicare

Special Enrollment Period (SEP)

If you delayed Medicare because you had employer coverage, an SEP lets you enroll without late penalties after that coverage ends

• When: Timeframes vary. Most SEPs last 2 months, but some (like after losing employer coverage) can give you up to 8 months. Check your exact timeframe at medicare.gov.

General Enrollment Period (GEP)

If you missed your Initial Enrollment Period and don’t qualify for a Special Enrollment Period, the GEP lets you enroll, but penalties may apply.

• When: Jan. 1 – Mar. 31 (coverage begins July 1)
• Penalty risk: Late enrollment penalties may apply

Step 3: Choose your coverage

Medicare has four different parts:

• Original Medicare Part A: Hospital coverage
• Original Medicare Part B: Medical coverage
• Part D: Prescription drug coverage
• Medicare Advantage (Part C): Combines Parts A, B, and often D, with extra benefits.

Step 4: Compare plans and costs

Evaluate your health care needs and budget. Original Medicare vs. Medicare Advantage differ in coverage, provider networks and out-of-pocket costs.

Step 5: Enroll on time

Sign up for Original Medicare through Social Security or Medicare.gov during your enrollment window to avoid late penalties. 

If you want additional coverage, such as a Medicare Advantage plan, make sure to enroll in that as well—right after you’ve signed up for Original Medicare. Priority Health has Medicare Advantage plans with extra benefits and local support. See why more individuals choose us than any other plan in Michigan.¹

Step 6: Review Annually

Medicare isn’t “set and forget.” Each year, review your plan during Open Enrollment (Oct. 15 – Dec. 7) to ensure it still meets your needs.

Frequently asked questions

Why understanding enrollment periods matters

Knowing Medicare enrollment periods is essential to avoid late penalties, prevent gaps in coverage and keep your health care costs under control. Each period offers specific opportunities to sign up, switch plans or add coverage. By understanding these timelines, you can make informed decisions and ensure your plan fits your health needs and budget.

¹ According to July 2025 monthly enrollment from the Centers for Medicare and Medicaid Services (CMS). Priority Health Medicare Advantage plans have the highest volume of enrollments in Michigan when compared to other carriers.

² Priority Health has been named to Newsweek’s America’s Best Customer Service 2025 list. Based on an independent survey of U.S. customers who have either made purchases, used services, or gathered information about products or services in the past three years.