Medicare is the federal program most people over 65 use, but you have real choices within it

When you turn 65, you become may be able to access for Medicare, a federal health insurance program that covers hospital stays, doctor visits, and some prescription drugs. You do not have to enroll automatically — you have to sign up during your enrollment window, which starts three months before the month you turn 65 and runs for seven months total. Missing this window can cost you permanently higher premiums, so the timing matters.

Medicare has different parts, and you choose which combination fits your situation. Part A covers hospital care. Part B covers doctor visits and outpatient care. Part D covers prescription drugs. You can also choose between Original Medicare (Parts A and B through the government) or Medicare Advantage (a private insurance plan that includes Parts A, B, and usually D). Each path has different costs, different doctors you can see, and different coverage limits.

If you are still working and have health insurance through your job, you may not need to enroll in Medicare right away — but the rules are specific about when you can delay without penalty. If you have a spouse who is younger and covers you on their plan, similar rules apply. Understanding your own situation before your 65th birthday prevents expensive mistakes later.

Key Takeaways

  • Medicare enrollment opens three months before you turn 65 and closes seven months after; missing this window triggers permanent premium increases.
  • Original Medicare (Parts A and B) lets you see any doctor who accepts Medicare, but you pay a deductible and coinsurance; Medicare Advantage plans have lower out-of-pocket costs but restrict which doctors you can use.
  • Part D (prescription drug coverage) must be added separately if you choose Original Medicare, and delaying enrollment can raise your premiums permanently.
  • Medigap policies are supplemental insurance sold by private companies that cover costs Original Medicare does not, such as deductibles and coinsurance.
  • If you cannot afford Medicare premiums or out-of-pocket costs, your state may have programs that help pay them based on your income.

Original Medicare versus Medicare Advantage: what you actually pay

With Original Medicare, you pay a monthly premium for Part B (around $165 in 2024, though this varies by income), a deductible when you use hospital or doctor services, and coinsurance (a percentage of the cost) after you meet the deductible. You can see any doctor in the country who accepts Medicare. There is no network restriction. If you need a specialist, you do not need a referral.

Medicare Advantage plans are sold by private insurance companies and bundle Parts A, B, and usually D into one plan. Monthly premiums are often lower or zero, and out-of-pocket costs are capped — once you hit that cap, the plan pays everything else for the year. The trade-off is that you can usually only see doctors in the plan's network, and you often need referrals to see specialists. If you travel frequently or live part of the year in another state, network restrictions can be a real problem.

The choice depends on your health, your doctors, and what you can afford upfront. Someone with multiple chronic conditions and regular specialist visits might pay less with Medicare Advantage's capped costs. Someone who sees doctors rarely and values flexibility might pay less with Original Medicare. Run the numbers for your specific doctors and medications before you choose — the difference can be hundreds of dollars a year.

Prescription drug coverage and how to avoid overpaying

If you choose Original Medicare, you must add Part D (prescription drug coverage) separately through a private insurance company. You pick a plan during the same enrollment window as Parts A and B. Plans vary widely in which drugs they cover and what you pay, so comparing plans matters even if you only take one or two medications.

Part D has a coverage gap — once you and your plan have spent a certain amount on drugs (around $5,100 in 2024), you enter the "donut hole" and pay more out of pocket until you hit catastrophic coverage. Catastrophic coverage then kicks in and you pay a small percentage of the cost. This gap shrinks every year by law, but it still exists. Knowing whether your drugs fall into this gap helps you budget.

If you have Medicare Advantage, prescription drug coverage is usually included in the plan, so you do not enroll in Part D separately. However, you should still check which drugs the plan covers and what you will pay, because coverage varies by plan and by pharmacy.

Medigap: supplemental insurance that covers what Medicare does not

Medigap (also called Supplement insurance) is sold by private insurance companies and covers costs that Original Medicare leaves you responsible for — deductibles, coinsurance, and copayments. It does not cover prescription drugs, long-term care, dental, vision, or hearing aids. If you choose Original Medicare, Medigap is optional but common, especially if you want predictable costs.

Medigap plans are standardized by the federal government, so a Plan G from one company covers the same things as a Plan G from another company. The only difference is price. This means you can shop purely on cost. Plans are labeled A through N, and each letter covers a different combination of costs. Plan G is currently the most popular because it covers most of what Original Medicare does not, except the Part B deductible.

You have a six-month window starting when you turn 65 and enroll in Medicare Part B to buy Medigap without medical underwriting — meaning the insurance company cannot deny you or charge you more based on your health. If you wait past this window, the company can refuse to sell you a policy or charge you significantly more. This window is one of the most important deadlines in Medicare, and many people miss it by accident.

State programs that help pay Medicare costs if your income is low

If your income is low enough, your state may cover some or all of your Medicare premiums and out-of-pocket costs through programs with names like Medicaid Buy-In, may have access to Medicare Beneficiary (QMB), or Specified Low-Income Medicare Beneficiary (SLMB). These are joint federal-state programs, so what is available depends on where you live and your exact income.

To learn about you may have access to, contact your state Medicaid office or call 211 (a free referral service). Have your income and asset information ready. If you may have access to, the program can pay your Part B premium, your Part D premium, your deductible, and your coinsurance — which can add up to thousands of dollars a year. The application process is straightforward, but you have to know the program exists and take the step to ask.

Enrollment deadlines and what happens if you miss them

Your Initial Enrollment Period runs for seven months: three months before the month you turn 65, the month you turn 65, and three months after. If you enroll in Part A and Part B during this window, you pay standard premiums. If you enroll late, your Part B premium increases by 10 percent for every 12 months you delayed — and this increase is permanent, for life.

If you have coverage through an employer (yours or a spouse's), you may be able to delay Part B enrollment without penalty, but you must enroll within eight months of losing that coverage. The rules are strict: if your employer coverage ends and you do not enroll in Part B within this window, you will face the permanent premium increase. Document the date your coverage ended so you can prove you were covered.

For Part D, if you go without prescription drug coverage for more than 63 days in a row, you pay a permanent penalty on top of your Part D premium. This penalty stays with you as long as you have Medicare. If you do not take prescription drugs now but might later, enrolling in Part D anyway (even in a cheap plan) protects you from this penalty.

When to enroll and how to do it

Start three months before your 65th birthday. Go to Medicare.gov and create an account, or call 1-800-MEDICARE. You can enroll online, by phone, or in person at your local Social Security office. Have your Social Security number, birth date, and citizenship information ready. If you are enrolling in Part D or Medicare Advantage, have a list of your current medications and doctors so you can compare plans accurately.

If you are already receiving Social Security benefits, Medicare will enroll you automatically in Parts A and B starting the month you turn 65. You do not have to do anything. However, you still need to enroll in Part D or choose a Medicare Advantage plan if you want drug coverage — automatic enrollment does not include these. If you are not yet receiving Social Security, you must enroll manually.

After you enroll, you will receive a Medicare card in the mail within two weeks. Keep it with you at all appointments. If you choose Medicare Advantage or Part D, your coverage starts on the first day of the month you turn 65 (or the first of the following month if you enroll late in your birthday month).

Frequently Asked Questions

What if I am still working at 65 and have health insurance through my job?

You can delay enrolling in Medicare Part B without penalty as long as your employer coverage continues. When your coverage ends (usually at retirement), you have eight months to enroll in Part B. You must still enroll in Part A at 65 unless you are actively working and your employer has fewer than 20 employees. Document the date your employer coverage ends so you can prove you were covered when you eventually enroll.

Can I switch from Original Medicare to Medicare Advantage or back again?

Yes, during the Annual Enrollment Period (October 15 to December 7 each year), you can switch plans. If you switch from Original Medicare to Medicare Advantage, you lose Medigap coverage and cannot get it back without medical underwriting (which may deny you or charge more). If you switch from Medicare Advantage to Original Medicare, you have a one-time right to buy Medigap without medical underwriting, but only if you buy it within 63 days of losing the Advantage plan.

Do I need both Medicare Advantage and Medigap?

No. Medigap is only used with Original Medicare. If you choose Medicare Advantage, you do not buy Medigap — the Advantage plan is your only coverage. Buying both would be redundant and wasteful. If you have Medigap and switch to Medicare Advantage, your Medigap policy ends.

What if my medications are expensive and I hit the Part D donut hole?

Once you enter the donut hole, you pay more out of pocket until your total spending reaches catastrophic coverage (around $7,050 in 2024). At that point, you pay only a small percentage of drug costs for the rest of the year. Some medications have manufacturer discounts in the donut hole. Ask your pharmacist or doctor if your drugs may have access to. You can also switch to a different Part D plan during the Annual Enrollment Period if your current plan's coverage is not working for you.

What if I cannot afford my Medicare premiums?

Contact your state Medicaid office or call 211 to ask about programs that pay premiums and out-of-pocket costs based on income. These programs exist in every state but have different names and income limits. You may may have access to even if you do not think you do. The application is free and takes about 20 minutes.