Medicare is a federal health insurance program primarily for individuals aged 65 and older. However, younger people may also qualify if they have certain disabilities, End-Stage Renal Disease (ESRD), or Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease.

How Eligibility for Medicare Works

Some individuals are enrolled in Medicare automatically, while others must sign up manually. The process depends on whether you’re already receiving retirement or disability benefits from Social Security before turning 65.

Before Age 65

If you apply for retirement benefits from Social Security (or the Railroad Retirement Board) at least four months before your 65th birthday, you’ll be automatically enrolled in Medicare Part A (Hospital Insurance) and Part B (Medical Insurance) once you turn 65.

Even with automatic enrollment, you'll still need to make important choices about your coverage, such as whether to add a prescription drug plan.

If you don’t plan to claim Social Security benefits right away but still want Medicare when you turn 65, you’ll need to actively sign up.

After Age 65

If you delay signing up for Social Security benefits beyond age 65, you must contact Social Security directly to enroll in Medicare. Depending on your employment status and existing health insurance, it may be wise to wait before enrolling.

Parts of Medicare

Medicare is divided into several parts, each offering different types of coverage:

Part A: Hospital Insurance

Helps cover:

1. Inpatient hospital stays
2. Skilled nursing facility care
3. Hospice care
4. Some home health care services

Part B: Medical Insurance

Covers services such as:

1. Doctor visits and outpatient care
2. Home health care
3. Durable medical equipment (e.g., walkers, hospital beds)
4. Preventive services like screenings and vaccines

Part D: Prescription Drug Coverage

Part D helps cover the cost of prescription medications. It’s offered through private insurance companies approved by Medicare and can be added to Original Medicare or included in some Medicare Advantage plans.

Medicare Supplement Insurance (Medigap)

Medigap is extra coverage you can purchase from private insurers to help cover out-of-pocket costs in Original Medicare. Plans are standardized and labeled by letters (e.g., Plan G, Plan K), and the benefits are the same across insurers within the same plan type.

Choosing Your Medicare Coverage

When you first become eligible and at specific times of the year, you can choose how to receive your Medicare coverage:

Option 1: Original Medicare

Includes Part A and Part B. You can:

1. Add Part D for prescription drug coverage
2. See any doctor or hospital that accepts Medicare across the U.S.
3. Purchase Medigap to help pay costs not covered by Original Medicare

Option 2: Medicare Advantage (Part C)

Offered by private companies, these bundled plans typically include:

1. Part A, Part B, and usually Part D
2. Additional benefits not offered by Original Medicare
3. A network of providers you must use (in most cases)
4. Different out-of-pocket costs and possibly an additional premium

How to Join a Medicare Plan

To enroll in a Medicare health or drug plan, you must:

1. Have both Part A and Part B
2. Live in the plan’s service area
3. Be a U.S. citizen or lawfully present in the country
4. Have your Medicare number and coverage start dates

Medicare Enrollment Periods

Initial Enrollment Period

When: Begins 3 months before and ends 3 months after you get Medicare

You can: Join any Medicare Advantage or drug plan

Coverage start: Depends on when the plan receives your enrollment

Initial Enrollment for Part B (if you already have Part A)

When: 3 months before and up to 2 months after your Part B starts

You can: Join any Medicare Advantage plan

Coverage start: The month after enrollment

Annual Open Enrollment Period

When: October 15 to December 7

You can:

   Switch between Medicare Advantage and Original Medicare

   Join, drop, or switch drug plans

Coverage start: January 1 of the following year

Medicare Advantage Open Enrollment Period

When: January 1 to March 31

Eligible if: You already have a Medicare Advantage Plan

You can: Switch plans or return to Original Medicare and join a drug plan

Coverage start: First of the month after the request is processed

Special Enrollment Periods

When: Varies based on life events such as:

   Moving to a new location

   Losing employer coverage

   Qualifying for Medicaid or Extra Help

You can: Join or switch Medicare Advantage or drug plans

Coverage start: Usually the first of the month after the plan receives your request

Notes

1. Medicare is not one-size-fits-all—you’ll need to make informed choices based on your health needs, finances, and lifestyle.
2. Timing matters: enrolling at the right time can help you avoid late penalties and coverage gaps.
3. Understand your options clearly—whether you choose Original Medicare with optional add-ons or a Medicare Advantage plan, each route has pros and cons.