Medicare Advantage or Medigap: which is better?

If Medicare Advantage costs less every month, why doesn’t everyone take it? Because the real price isn’t the premium. It’s what happens the year you get seriously sick, and whether you can still change your mind once you do. For an affluent retiree, that question usually matters more than the monthly cost.

What you’re actually choosing between

Both paths start with Original Medicare, where for 2026 the standard Part B premium is $202.90 a month. From there you pick a lane.

• Medicare Advantage (Part C): a private plan that replaces Original Medicare. Low or zero extra premium, often with dental, vision, and drug coverage bundled in. The catch is a network of doctors, referrals, and prior approvals for big-ticket care.
• Medigap (a supplement) plus Original Medicare: you keep Original Medicare and add a supplement that pays the gaps, plus a standalone Part D drug plan. Higher premium, but you can see any doctor who takes Medicare, anywhere in the country, with no network and no referrals.

The glossary on Medicare Parts A, B, C, and D lays out the alphabet if it’s a blur.

The tradeoff that actually decides it

Medicare Advantage works beautifully right up until you need expensive care. Then the network and the prior-approval process become the whole story. You may be steered to in-network specialists, denied access to a top cancer center out of state, or stuck waiting on an approval for a procedure you and your doctor already agreed on.

Medigap costs more in premium precisely because it removes those frictions. You pay a known monthly amount in exchange for the freedom to walk into any Medicare-accepting hospital in the country, including the marquee specialty centers, without asking permission. For someone who can comfortably afford the premium, that’s often money well spent.

The hidden price: the one-way door

Here’s the part the low premium hides, and it’s the one that bites in later life. You can almost always switch from Medigap to Medicare Advantage. Going back the other way is the trap.

When you first enroll at 65, you can buy any Medigap policy regardless of your health. After that initial window, in most states an insurer can make you answer health questions, and can charge more or refuse you outright. So the retiree who picks Advantage at 65 to save money, then develops a serious condition at 78 and wants Medigap’s freedom, may find the door has quietly locked. The choice you make while healthy can become permanent the moment you’re not.

That asymmetry is why I treat this as a decision to make with your future, sicker self in mind, not just this year’s budget. The deeper Medigap versus Advantage analysis for larger households walks through it.

If your finances are large

When the premium is a rounding error in your budget, the math tilts toward Medigap, because what you’re really buying is access and the freedom to never be told no on care. The savings from Advantage matter most when money is tight, and least when it isn’t.

One more wrinkle for higher incomes: your Medicare premiums aren’t fixed. Cross certain income lines and you pay IRMAA, an income-based surcharge on Parts B and D, set by your tax return from two years earlier. That surcharge applies whichever path you choose, so managing the income that triggers it is its own conversation.

Cheaper every month and costlier when it counts is the Medicare Advantage bargain. Decide it as if you’ll one day be your sickest self, because that’s the version of you the choice is really for.