Original Medicare — Part A (hospital insurance) and Part B (medical insurance) — covers a great deal, but it does not cover everything. Deductibles, coinsurance, and copayments add up, and unlike many other types of insurance, Original Medicare has no yearly limit on what you can pay out of pocket. That is why many people add something on top: either a Medicare Advantage plan (Part C) or a Medigap policy (Medicare Supplement Insurance). The two approaches solve the same problem in very different ways. Here is how to think about the trade-offs.
How Medicare Advantage (Part C) works
Medicare Advantage plans are offered by private companies approved by Medicare. They bundle Part A, Part B, and usually Part D prescription drug coverage into a single plan — and many add extras Original Medicare does not cover, such as dental, vision, hearing, or fitness benefits. Most plans work through provider networks (often HMO or PPO designs), so you generally get the best value when you use in-network doctors and hospitals. You still pay your Part B premium, plus whatever premium and cost-sharing the plan itself sets.
How Medigap works
Medigap policies are also sold by private companies, but they are designed to sit alongside Original Medicare rather than replace it. A Medigap policy helps pay some of the out-of-pocket costs Original Medicare leaves behind — such as coinsurance, copayments, and, depending on the plan letter, the Part A or Part B deductible. In most states, Medigap plans are standardized into lettered options (A through N), so the same letter means the same basic benefits no matter which company sells it. You can generally see any doctor or hospital that accepts Medicare nationwide, and because Medigap does not include drug coverage, most people pair it with a separate Part D plan.
The key trade-offs, side by side
- Provider choice: Medigap lets you see any provider that takes Medicare, with no referrals. Medicare Advantage usually costs least inside its network and may require referrals.
- How you pay: Medigap typically means a higher monthly premium but very predictable costs when you need care. Medicare Advantage often has lower premiums but more cost-sharing (copays, coinsurance) as you use services.
- Drug coverage: Usually built into Medicare Advantage plans. With Medigap, you buy a separate Part D plan — an extra decision, but also an extra choice.
- Extra benefits: Dental, vision, and hearing extras are common in Medicare Advantage. Original Medicare plus Medigap generally does not include them.
- Changing later: You can switch between paths during enrollment windows, but in most states, buying Medigap outside your initial enrollment period can involve medical underwriting — so the decision you make at 65 can be hard to reverse.
Questions to ask yourself
- How important is it to keep your current doctors, or to see specialists without referrals?
- Do you travel often or split time between states?
- Would you rather pay more each month for predictable costs, or pay less monthly and more when you need care?
- How much do dental, vision, and hearing benefits matter to you?
- Are you comfortable comparing networks and formularies each year during open enrollment?
There is no universally “better” option — only the better fit for your health, your doctors, and your budget. This article is general information, not personal advice. For official details, visit medicare.gov or call 1-800-MEDICARE.