Medicare looks simple on the surface — you’re 65, you sign up, you get coverage. The reality is closer to a maze built by people who profit when you pick wrong. Every fall, between October 15 and December 7, you get one chance to switch your plan for the following year. Get it wrong and you can spend the next twelve months paying for prescriptions your plan doesn’t cover, doctors you can’t see, or a deductible that resets when you finally need care.
The Two Tracks Most People Don’t Realize They’re Choosing Between
Original Medicare (Parts A and B) is run by the federal government. You can see any doctor or hospital in the country that accepts Medicare, which most do. There is no network. The trade-off is that there is no out-of-pocket maximum, and you pay 20% of every outpatient bill with no cap. A single hospital stay can run into five-figure coinsurance bills if you don’t have supplemental coverage.
Medicare Advantage (Part C) is sold by private insurers and bundles Parts A, B, and usually Part D drug coverage into one plan. Most plans advertise dental, vision, hearing, and gym memberships. The catch is the network — go out of network and you may pay full price or be denied entirely. Prior authorization is also common, even for procedures that Original Medicare would approve automatically, and denials are not always reversed on appeal.
The decision isn’t “which one is cheaper” because the answer depends on your doctors, your prescriptions, and whether you travel. It depends on your actual usage patterns for the year ahead, including procedures you can already see coming.
Five Numbers That Matter More Than the Premium
Advertised monthly premiums are the least useful number on a Medicare plan’s summary of benefits. Here’s what to look at first.
- Annual out-of-pocket maximum. Only Medicare Advantage plans have one, and they vary from about $3,000 to $8,850 for in-network care in 2026. Original Medicare has no cap at all, which is why some people buy a Medigap supplement alongside it.
- Your specific drugs on the formulary. Don’t trust “we cover Part D drugs.” Every plan has a tiered list, and the same medication can be $7 a month on one plan and $90 on another. The Medicare Plan Finder at medicare.gov lets you enter your exact prescriptions and your preferred pharmacy — use it, don’t guess.
- Your doctors in the network. Call each doctor’s office and ask which Medicare Advantage plans they accept for the upcoming year. Networks change annually. A plan your doctor took in 2025 may not be in network for 2026.
- The deductible, especially for Part D. Some plans charge $0 medical deductible but a $590 drug deductible. Others fold the deductible into copays. Compare what you actually pay when you fill a prescription, not the headline number.
- Travel coverage. Original Medicare works in any U.S. state. Most Advantage plans are regional HMOs or PPOs with limited or no coverage outside their service area. If you split time between two states or travel frequently to see family, this alone can decide it.
Medigap Has a Window Most People Miss
Medigap (Medicare Supplement Insurance) is private insurance that pays the 20% coinsurance Original Medicare doesn’t cover. It’s a separate purchase from a Part D drug plan. The trick: you get a six-month Medigap open enrollment window starting the month your Part B begins. During that window, insurers have to sell you any plan they offer regardless of pre-existing conditions.
After that window closes, insurers in most states can ask health questions and deny you coverage or charge more based on your conditions. People who try to switch from Medicare Advantage back to Original Medicare plus Medigap years later often find they cannot get a Medigap plan at all, or only at a price that makes it pointless.
If you think you might want Original Medicare long-term, buy the Medigap plan during your initial window even if it feels expensive now. It is dramatically harder to add later, and the cost of waiting is rarely obvious until you’re already sick.
The Part D “Donut Hole” Is Still There, Just Renamed
The coverage gap — once called the donut hole — was supposed to close in 2020 but the underlying mechanics are still in place. In 2026, after your drug spending hits a certain threshold, your out-of-pocket costs on brand-name drugs settle at roughly 25% of the price. The catastrophic coverage kicks in only after you’ve spent several thousand dollars out of pocket for the year.
For anyone on a brand-name medication, this is the single biggest reason to compare Part D plans annually. Two plans with similar premiums can differ by thousands of dollars once you hit the gap. Even if you don’t switch plans, the “same” plan from last year can change its formulary and pharmacy network enough to change your costs by hundreds of dollars.
What to Do in the Six Weeks Before December 7
Don’t wait until late November to start. Insurer call centers get slammed, and the people answering phones are not always trained to walk you through the comparison math.
- Pull your list of prescriptions with exact dosages and frequencies.
- Pull your list of doctors, including any specialists you saw this year.
- Run your drugs through the Medicare Plan Finder for next year’s plans and write down the estimated total annual cost, not the monthly premium.
- Call your doctors’ offices and ask which plans they expect to be in network for the coming year.
- If you have an Advantage plan and want to switch back to Original Medicare, confirm Medigap eligibility with at least two insurers in your state before you make the change.
Open enrollment runs October 15 through December 7 every year. Outside that window, you can usually only switch if you qualify for a special enrollment period — moving, losing employer coverage, or entering a care facility. Treat the fall window as your one scheduled checkup for your coverage.
The cheapest plan on paper and the right plan for you are often two different things. Spend an hour with your drug list, your doctor list, and the Medicare Plan Finder. The math is boring, but the difference between guessing and comparing is often a thousand dollars a year or a denied referral when you actually need care.
