No single Medicare plan covers everything, and plans that claim to are misleading you

Medicare has strict limits on what any plan can cover, no matter which one you choose. Original Medicare (Part A and Part B) does not cover dental, vision, hearing aids, or most prescription drugs. Medicare Advantage plans (Part C) can add some of these benefits, but they come with networks, referral requirements, and out-of-pocket limits that vary widely. Medigap plans (supplemental insurance) fill gaps in Original Medicare but do not add the benefits Medicare itself does not cover. The "best" plan for you depends on what you actually need, not on finding one that covers everything — because that plan does not exist.

Understanding what each plan type does and does not cover is the only way to make a real comparison. This guide walks you through the permanent gaps in Medicare, the trade-offs in each plan type, and how to find the plan that matches your doctors, drugs, and budget.

Key Takeaways

  • Medicare Part A and Part B have permanent gaps: no dental, vision, hearing aids, or most prescription drugs, regardless of which plan type you choose.
  • Medicare Advantage plans can include dental and vision but require you to use in-network providers and may charge higher copays than Original Medicare.
  • Medigap plans reduce your out-of-pocket costs under Original Medicare but do not add benefits that Medicare itself does not cover.
  • The best plan for you depends on your doctors, prescriptions, and budget — not on finding one that covers everything.
  • You can change plans during Open Enrollment (October 15 to December 7 each year) or if you have a may have access to life event.

What Medicare actually covers and what it does not

Original Medicare Part A covers hospital stays, skilled nursing facility care, hospice, and some home health services. Part B covers doctor visits, outpatient care, lab tests, and some equipment. Neither part covers dental work, eyeglasses, hearing aids, or routine foot care. Part D (prescription drug coverage) is separate and varies by plan — some drugs are not covered at any price, and those that are covered may require prior approval from your insurer.

This is not a gap you can close by picking the right plan. These are permanent exclusions written into Medicare law. A Medicare Advantage plan can add dental and vision benefits on top of Parts A and B, but it cannot change what Parts A and B themselves cover. A Medigap plan can pay some of the costs Medicare does not cover (like coinsurance and deductibles), but it cannot add benefits that Medicare itself does not offer. If you need dental work, you will pay for it out of pocket or through a separate private dental plan, no matter which Medicare plan you choose.

Medicare Advantage: More benefits, but with trade-offs

Medicare Advantage plans (Part C) are sold by private insurers and must cover everything Original Medicare covers, but they can add dental, vision, hearing, and other benefits. Many plans include a gym membership or transportation to medical appointments. The catch is that you must use doctors and hospitals in the plan's network, and you usually need a referral to see a specialist.

Out-of-pocket costs under Medicare Advantage can be lower than Original Medicare if you use in-network providers and stay within the plan's formulary for drugs. But if you see an out-of-network doctor or need a drug the plan does not cover, you pay the full cost yourself — there is no safety net. Plans also change their networks and drug coverage every year, so a doctor you see today may not be in-network next year. Medicare Advantage plans have an annual out-of-pocket maximum (the amount you pay before the plan covers everything at 100 percent). This maximum varies by plan and by year, but it provides a ceiling on your costs. Original Medicare has no such maximum.

Medigap: Lower costs, but only for what Medicare covers

Medigap plans (supplemental insurance) work alongside Original Medicare. They pay some or all of the costs that Medicare does not — copays, coinsurance, and deductibles. They do not add new benefits. If Medicare does not cover something, Medigap will not either.

Medigap plans are labeled A through N, and each letter covers a different set of costs. Plan G, for example, covers the Part B deductible and most coinsurance. Plan N covers copays and coinsurance but not the Part B deductible. You choose which plan fits your budget and your expected medical use. Unlike Medicare Advantage, Medigap plans have no network — you can see any doctor who accepts Medicare. The trade-off is that you pay a monthly premium for Medigap on top of your Part B premium, and you still need to buy Part D (prescription drug coverage) separately. Medigap is most useful if you have predictable medical needs and want to avoid surprises, because you know exactly what your costs will be.

Prescription drug coverage: A separate decision

Part D is not automatic. If you have Original Medicare and a Medigap plan, you must choose a Part D plan separately. If you have Medicare Advantage, drug coverage is usually included, but the drugs covered and the copays vary by plan.

Part D plans change their drug lists every year. A medication you take today may move to a higher tier (higher copay) or be removed from the formulary entirely next year. You can switch Part D plans during Open Enrollment without penalty, so it is worth reviewing your plan each October to see if a different one would cost less for your specific drugs. Some drugs are not covered by any Part D plan at all — these are usually newer, very expensive medications. If you take one of these drugs, you pay the full cost yourself, though you may be able to work with your doctor to find a covered alternative.

How to choose the plan that works for you

Start by listing your current doctors, hospitals, and prescription drugs. Then use the Medicare Plan Finder tool on Medicare.gov to see which plans in your area include your doctors in-network and cover your drugs. Compare the total cost: monthly premiums plus expected copays and coinsurance based on your actual medical use.

If you see many specialists or take multiple prescription drugs, Medicare Advantage may cost less because of the out-of-pocket maximum. If you have a stable set of doctors and want to avoid surprises, Original Medicare with Medigap may be better, even if the monthly premium is higher. Do not choose based on what the plan name suggests or what a sales agent tells you it covers. Read the Summary of Benefits and Coverage document for any plan you are considering — it lists exactly what is and is not covered, and what you will pay.

When you can change plans

Open Enrollment runs from October 15 to December 7 each year. During this period, you can switch from Original Medicare to Medicare Advantage, from Medicare Advantage to Original Medicare, or from one plan to another. Changes take effect January 1.

If you have a may have access to life event — you move out of your plan's service area, lose other coverage, or experience a death in your family — you may be able to change plans outside of Open Enrollment. You usually have 60 days from the event to make the change. If you miss Open Enrollment and do not have a may have access to event, you are locked into your current plan until the next Open Enrollment period. There is no exception for changing your mind or finding a better deal.

Frequently Asked Questions

Can I get dental and vision coverage under Original Medicare?

No. Original Medicare does not cover dental, vision, or hearing aids. You can buy a separate dental or vision plan from a private insurer, but these are not part of Medicare. Medicare Advantage plans can include dental and vision, but coverage and copays vary by plan.

What if I need a drug that is not on my plan's formulary?

You can ask your doctor to request a coverage exception, which the plan may grant if there is no suitable alternative. If the exception is denied, you can file an appeal. You can also switch to a different Part D plan during Open Enrollment that does cover the drug, though you will have to wait until October to make the change.

Is Medicare Advantage cheaper than Original Medicare with Medigap?

It depends on your health and your doctors. Medicare Advantage has lower monthly premiums but higher copays per visit. Original Medicare with Medigap has higher premiums but predictable costs. Use the Medicare Plan Finder to compare the total cost for your specific situation.

Can I have both Medicare Advantage and Medigap?

No. If you are enrolled in Medicare Advantage, you cannot buy a Medigap plan. If you switch from Medicare Advantage to Original Medicare, you can then buy Medigap, but you may lose some protections if you wait more than 63 days after leaving Medicare Advantage.

What happens if my doctor leaves the Medicare Advantage network?

You will have to find a new in-network doctor or pay out-of-network rates. Some plans allow you to continue seeing an out-of-network doctor at in-network rates for a limited time if the doctor leaves the network, but this varies. Check your plan's policy before enrolling.