Medicare 101: What to Know Before You Turn 65

Your essential guide to enrollment, coverage options, and avoiding costly mistakes.

If your 65th birthday is on the horizon, there’s a good chance you’ve already been bombarded with ads about Medicare enrollment. Some sound helpful, others feel like legal fine print disguised as a postcard. The truth is, Medicare is both straightforward and confusing—straightforward in that everyone gets Part A (hospital insurance) if they paid into the system, but confusing when you realize there are multiple parts (A, B, C, and D), enrollment windows, and penalties for missing deadlines.

According to the Kaiser Family Foundation, more than 65 million Americans were enrolled in Medicare as of 2023, with nearly half choosing Medicare Advantage plans over Original Medicare. Yet every year, thousands of people pay lifelong penalties simply because they didn’t sign up on time.

When to Sign Up

Your Initial Enrollment Period begins three months before the month you turn 65, includes your birthday month, and extends three months after. That’s a seven-month window. Miss it, and you could face a 10% premium penalty for every year you delay signing up for Part B—for life.

Parts A, B, C, and D Explained

Think of Medicare like a menu with required and optional items:

• Part A: Hospital insurance (usually premium-free).

• Part B: Medical insurance (doctor visits, outpatient care). Monthly premium in 2025 is $174.70.

• Part C (Medicare Advantage): All-in-one plans offered by private insurers, often with extras like vision, dental, or gym memberships.

• Part D: Prescription drug coverage, essential if you need medications.

Harvard health economist David Cutler once said, “Health insurance is complicated not because it has to be, but because it serves so many competing interests.” Medicare is a case study in that observation.

Original Medicare vs Medicare Advantage

This is where most people get stuck. Original Medicare covers the basics but leaves gaps. That’s why many purchase a Medigap (supplemental) plan. By contrast, Medicare Advantage plans bundle services into one policy, often with lower premiums but limited provider networks.

According to CMS data, 51% of all Medicare beneficiaries are now enrolled in Medicare Advantage—up from just 19% in 2007. That shift shows how much appetite there is for bundled, “one card for everything” solutions.

How Current Coverage Affects Timing

Still working at 65? If you’re covered under your employer’s plan and the company has more than 20 employees, you may be able to delay Medicare without penalty. But rules differ if your employer is smaller, so double-check. The U.S. Department of Labor notes that coordination of benefits is a frequent source of confusion—and mistakes here can cost thousands.

Prescription Coverage Matters

Skipping Part D because you don’t take medications now can be risky. The penalty for late enrollment grows the longer you wait. The AARP estimates that even a healthy 65-year-old has a 70% chance of needing significant prescription drug coverage within 20 years.

Avoiding Common Pitfalls

1. Don’t wait until after your birthday—apply early in your enrollment window.

2. Check employer coverage rules before deferring.

3. Compare Medicare Advantage and Medigap side by side.

4. Plan for prescriptions—Part D matters more than you think.

Medical Disclaimer

The information provided in this article is for educational and informational purposes only and is not intended as medical advice. It should not be used to diagnose, treat, cure, or prevent any medical or mental health condition. Always seek the guidance of a qualified healthcare professional or licensed mental health provider with any questions you may have regarding a medical condition, diagnosis, or treatment. Never disregard professional medical advice or delay seeking it because of something you have read here.