The Three Main Coverage Paths
Medicare offers two main paths:
- Original Medicare (Parts A and B) — the government program. You pick your doctor and hospital.
- Medicare Advantage (Part C) — private insurance plans that bundle coverage. They usually include prescription drugs (Part D) and sometimes dental, vision, or hearing.
With Original Medicare, you can add drug coverage (Part D) and a Medigap plan separately to lower your costs. With Medicare Advantage, drugs are usually included—but you can't add Medigap.
Original Medicare + Optional Medigap & Part D
How it works
The federal government runs Original Medicare. Part A pays for hospital stays, nursing care, and hospice. Part B pays for doctor visits and preventive care. Once you're in Parts A and B, you can pick a prescription drug plan (Part D) from private companies—or skip it if you don't take medications. Many people also add Medigap to pay less out of pocket.
Provider freedom
You can see any doctor or hospital that takes Medicare. No network limits. You don't need permission to see a specialist. This is helpful if you have doctors you trust or live where there are many specialists.
Cost structure
Original Medicare has a deductible (the amount you pay before Medicare helps) for Part A and Part B. You also pay copayments (a set amount per visit) or coinsurance (your percentage of a bill). There's no yearly limit on what you pay out of pocket. This is unpredictable and can be expensive.
That's where Medigap helps. Medigap plans (labeled A through N) pay some of your deductibles, copayments, and coinsurance. Each letter-named plan covers the same benefits in your state, so you shop only on price. Part D (drug coverage) has its own deductible and copayments that differ by plan.
Predictability vs. flexibility
Original Medicare plus Medigap gives you predictable costs. Once you pick a Medigap plan, you know what you'll pay. But you pay three separate premiums: Part B, Medigap, and Part D. These can go up each year.
There's one critical rule: If you enroll in Medigap within 6 months of turning 65 and signing up for Part B, insurers must take you without checking your health and can't charge you more. After that 6-month window closes, insurers can review your health, deny you, or charge extra. This window is once in your life—it's important.
Medicare Advantage (Part C)
How it works
Private insurance companies run Medicare Advantage plans. Medicare pays them each month to cover you. The company provides Part A, Part B, and usually Part D in one plan. The company sets the rules: which doctors you see, whether you need permission to see a specialist, which drugs it covers, and how much you pay.
Provider networks & referrals
Most Medicare Advantage plans are HMOs (Health Maintenance Organizations) or PPOs (Preferred Provider Organizations). HMO plans require you to use their doctors and get permission before seeing a specialist. PPO plans give you more freedom—you can see out-of-network doctors but pay more. It's harder to switch doctors mid-year with Medicare Advantage than with Original Medicare.
Cost structure
Medicare Advantage plans often cost $0 per month (besides Part B). But you pay copayments (a set amount per visit) and coinsurance (your share of a bill). Many plans cap what you pay each year—once you hit that cap, the plan pays 100%. But plans change every year (doctors drop out, copays go up, covered drugs change), and the yearly caps differ by plan.
Extra benefits
Many Medicare Advantage plans include dental, vision, hearing, or fitness benefits that Original Medicare doesn't. If you need these, it's a big plus. But they're extras added to the plan, not separate coverage.
Travel and continuity
If you travel or move away from your plan's service area, coverage can be limited. Original Medicare works everywhere in the U.S. and a bit overseas. Medicare Advantage is tied to a specific region and plan. If you move, you might need to pick a new plan.
Understanding Medigap (Medicare Supplement Plans)
What Medigap is
Medigap is extra coverage sold by private companies. It helps pay the copayments, coinsurance, and deductibles that Original Medicare leaves you to pay. Medigap only works with Original Medicare—it's not a replacement for it. The federal government sets what each Medigap plan covers. A Plan G from Company A covers the same benefits as a Plan G from Company B. Only the price changes between companies.
How Medigap plans are labeled
Medigap plans use letters: A, B, D, G, K, L, M, and N. Each letter covers a different mix of Original Medicare's cost-sharing. Plan G is comprehensive and covers most of your costs. Plan K covers less and has a yearly cap. Compare plans by looking at the official benefit chart, not company ads. In your state, all Plan G policies cover the same thing—you're just comparing price.
Critical timing: Medigap Open Enrollment
This matters: Within 6 months of turning 65 and signing up for Part B, apply for Medigap. Companies must accept you without checking your health, and they can't charge you more. This window happens once in your lifetime. If you wait, companies can check your health history, deny you, or charge more. Many people miss this deadline and regret it. For more, visit Medicare.gov.
Medigap and Medicare Advantage cannot mix
You can't buy Medigap if you have Medicare Advantage. If you switch from Medicare Advantage back to Original Medicare, you need to time it right or you'll lose your Medigap guarantee. This is why choosing between these paths early matters.
How the two manage your care differently
By law, Medicare Advantage covers everything Original Medicare covers—it can't cover less, and it often adds more. The real difference is how you get approval and access to care. Here's what matters:
- Prior authorization. Medicare Advantage plans often require pre-approval before you get a service. They check if it's medically necessary. A service can be delayed or denied even if it's supposed to be covered. Federal inspectors have found some denials were actually for care that Medicare would approve. Many denials are overturned when you appeal. Original Medicare requires little pre-approval now (one CMS test is trying it in six states for a few services). Either way, you can appeal a denial — see Your Rights.
- Networks. Medicare Advantage uses local networks. It's harder to keep your doctor if they're not in the network, and travel makes getting care harder. Some hospitals have stopped working with certain plans. Original Medicare works with any provider that takes Medicare, anywhere in the country.
- The balance. To make up for networks and pre-approval, Medicare Advantage usually has low or $0 premiums. It includes drugs, dental, vision, and hearing. It caps your yearly out-of-pocket costs. Original Medicare alone doesn't. Neither is "better"—they fit different situations. The choice matters most if you have health issues that need ongoing care.
Side-by-Side Comparison
| Feature | Original Medicare + Medigap/Part D | Medicare Advantage |
|---|---|---|
| Provider choice | Any Medicare provider, no network limits, no referrals needed | Network-based (HMO or PPO); HMOs require referrals; out-of-network costs more or not covered |
| Deductibles & copays | Original Medicare has deductibles; Medigap reduces or eliminates them | Vary by plan; often $0 premium with set copays per visit; many plans have annual out-of-pocket caps |
| Predictability of costs | With Medigap: fairly predictable (know your copay and premium in advance). Without Medigap: can be variable | Predictable up to annual out-of-pocket cap; after cap, plan pays 100% |
| Prescription drugs | Buy separate Part D plan; have your own deductible and formulary | Usually included in the plan; subject to plan's drug formulary and copays |
| Dental, vision, hearing | Not covered by Original Medicare or most Medigap plans (these are add-ons you buy separately) | Many plans include some or all of these; coverage varies by plan |
| Travel & portability | Original Medicare works everywhere in the U.S.; limited abroad. Medigap is portable — use any provider accepting it | Plan is region-specific; limited coverage outside service area; limited international coverage |
| Plan changes | Original Medicare is stable; Medigap and Part D plans can change; you can switch during Open Enrollment | Plan benefits and network can change yearly; you can switch during Open Enrollment but must requalify if you switch back to Original |
| Enrollment guarantee | Medigap guaranteed issue for 6 months after turning 65 and enrolling in Part B (one-time window) | No health screening; open to anyone eligible for Medicare |
| Switching paths | Can switch to Medicare Advantage during annual Open Enrollment, but losing Medigap means losing an enrollment guarantee if you want to return | Can switch to Original Medicare + Medigap during Open Enrollment, but Medigap enrollment rules apply if outside the 6-month window |
Questions to Ask Yourself
These questions help you think about which path fits your situation. They don't tell you what to pick.
- Do you have doctors you want to keep? Check if your doctors are in the Medicare Advantage plans near you. If they're not in-network, or if you like flexibility, Original Medicare works better.
- How much do you travel or move? If you travel a lot or move between states, Original Medicare is easier. If you stay in one area, Medicare Advantage works.
- Do you take many medications? Check if your drugs are covered and at what cost in Part D plans (for Original Medicare) and Medicare Advantage plans. Covered drugs (formularies) change each year.
- Do you value extra benefits? If you need dental, vision, or hearing and can't pay separately, Medicare Advantage may cost less. If you already have these covered by work or retirement, it doesn't matter.
- Do you prefer predictable or flexible costs? Medigap + Original Medicare locks in your costs. Medicare Advantage with a yearly cap is predictable too, but limited to the network. Flexible costs might lower your premiums.
- How do you feel about referrals and authorization? HMO plans require permission to see a specialist. Some people dislike this; others find it helpful. Original Medicare doesn't need referrals.
A common oversimplification worth avoiding
You'll hear people say: "Healthy people do better on Medicare Advantage. Less healthy people do better on Original Medicare." There's some truth to this. Advantage's low cost and yearly cap work well for people who use less care. Original Medicare plus Medigap gives unlimited access and steady costs for people who need a lot of care. But the rule is too simple. Here's why:
- Health changes, and the Medigap door can close. A healthy person who picks Advantage at 65 may not be able to switch to Original Medicare plus Medigap later if their health declines. Companies will check their health history (see the one-way door above). This choice affects decades, not just today.
- Original Medicare by itself has no out-of-pocket limit. "Less healthy → Original Medicare" only works if you buy Medigap too. You must afford it and qualify for it (outside your protected window). Without Medigap, costs can be unlimited.
- Health status is only one factor. Your budget, your drugs, whether your doctors accept the plan, how much you travel, and which plans exist in your county all matter. Plan quality varies by location.
Look at the factors above for your situation. Don't just follow a one-line rule.
Who tends to do well with each option
Some people really are better off with each path — the trick is recognizing which group you're in. These are general patterns, not rules. Both options are legitimate, individuals differ, and a specific plan matters more than any average. Use the tools below to see where you land.
Original Medicare + Medigap tends to fit people who…
- Want to keep specific doctors, or see any provider that takes Medicare
- Travel often or live in more than one state
- Have — or expect to develop — ongoing health conditions, and want predictable costs and few coverage hurdles
- Can afford a monthly supplement premium in exchange for that predictability
- Prefer to avoid referrals and prior authorization
- Want to lock in guaranteed Medigap access during their one-time window, to keep future flexibility
Medicare Advantage tends to fit people who…
- Are focused on a low or $0 monthly premium
- Are relatively healthy and use little care right now
- Stay mostly in one local area
- Want extra benefits like dental, vision, and hearing bundled in
- Are comfortable using a network and getting approvals for care
- Prefer one all-in-one plan and a single card
How each path handles common situations
The tradeoffs get concrete when you look at real situations. Here's how the two paths generally handle them. (Specific plans vary — always confirm with the plan.)
| Situation | Original Medicare (+ Medigap) | Medicare Advantage |
|---|---|---|
| Seeing a specialist | No referral needed; any specialist who takes Medicare | Often needs a referral (HMO); must be in-network |
| A planned surgery or procedure | Rarely needs pre-approval; any provider that takes Medicare | Often needs prior authorization; in-network provider |
| Using a specific hospital or cancer center | Covered if it takes Medicare (most do) | Only if it's in your plan's network |
| Getting care while traveling in the U.S. | Any provider that takes Medicare, nationwide | Emergencies covered; routine out-of-area care usually not |
| A very high-cost year | Medigap makes your share predictable; Original Medicare alone has no cap | Capped by the plan's yearly out-of-pocket maximum |
| A service is denied | Pre-approval is rare; you have appeal rights | More prior-auth denials; you have appeal rights |
| Dental, vision, hearing | Not covered (buy separately) | Often included as extra benefits |
| Moving to another state | Coverage travels with you | Usually must switch to a plan in the new area |
| Long-term nursing-home (custodial) care | Not covered — that's Medicaid | Not covered — that's Medicaid |
Making a Decision
Your choice depends on your doctors, health, budget, travel, and what you prefer. Both paths work for many people.
More Information
See also:
- Understanding Your Costs — detailed explanation of each type of cost in Original Medicare and Medicare Advantage.
- Enrollment & Deadlines — when you can enroll and what happens if you miss deadlines.
- Getting Help Paying — financial assistance programs for people with limited income.
- Medicare.gov Plan Finder — see plans and prices available in your area.
- State Health Insurance Assistance Program (SHIP) — find a free counselor near you.