The number printed largest on a Medicare Advantage mailer is the monthly premium, and in a lot of markets that number is zero. The number that actually decides whether a bad health year wrecks a budget is printed much smaller, usually deep inside a document called the Evidence of Coverage. It is the maximum out-of-pocket limit, or MOOP, and it is the ceiling on what a plan can make you pay for covered in-network medical care in a single year. For 2026, federal rules allow that ceiling to sit as high as $9,250 for in-network care, and $13,900 once out-of-network care is counted in plans that cover it, according to KFF's annual review of Medicare Advantage plans. Most plans set their limit below the legal maximum; KFF puts the average in-network limit at $5,421 this year. Open enrollment is the one window when you can act on that difference, so the useful work is learning to read past the premium.
Why a zero premium is a bet, and what the bet is on
A zero-premium plan is a wager that your health will hold. If it does, you keep the money you would have spent on premiums and the arrangement genuinely works in your favor. If it does not, the plan's cost-sharing takes over: copays for specialist visits, coinsurance on procedures, daily hospital charges. The MOOP is where all of that stops, which is why it functions less like fine print and more like the real price tag. A plan with a $9,000 limit is a plan that can cost you $9,000, and a hip replacement after a fall on the ice, or one cardiac procedure, can get you most of the way there in a single season.
This is also the honest way to compare Medicare Advantage against Original Medicare paired with a Medigap supplement. Medigap premiums look expensive next to zero, often a few hundred dollars a month depending on the state and plan letter. What that premium buys is predictability: small, steady costs instead of a large possible one. Neither structure is automatically right. A person with reliable savings and good health may reasonably prefer the Advantage math. A person who would have to drain an emergency fund to cover a five-figure year may sleep better paying monthly for the supplement. One caution worth knowing before you choose: in most states, after your initial window closes, Medigap insurers can review your health history and decline you or charge more. Moving from Advantage back to Original Medicare with a supplement later is often harder than the reverse trip, so this decision has more one-way character than the brochures suggest.
Prior authorization, the cost that never shows up on a statement
Advantage plans manage spending by requiring approval before certain care is delivered. This is nearly universal: KFF reports that 99 percent of enrollees are in plans that require prior authorization for at least some services, most often the expensive ones such as inpatient stays, skilled nursing care, and specialty drugs. Traditional Medicare rarely uses it.
For a healthy enrollee this is invisible. For someone facing surgery or an MRI, it can mean weeks of waiting while a reviewer who has never met them decides whether the care is necessary, and denials do happen even when the treating physician is emphatic. Appeals exist and often succeed, but an appeal is paperwork and phone calls at exactly the moment a person has the least energy for either. None of this appears in a plan's cost tables. It is still a cost, paid in time and stress, and people who have been through a serious diagnosis tend to weigh it heavily when they choose their next plan.
The drug side has its own ceiling now
Prescription costs run on a separate track from the medical MOOP. Federal law now caps what Part D enrollees pay out of pocket for covered drugs each year; the cap is $2,100 in 2026 per KFF's figures. For anyone taking an expensive medication for cancer, rheumatoid arthritis, or a heart condition, this is a genuine floor under the year, and it is worth factoring into the comparison.
The cap has a boundary, though: it applies only to drugs a plan covers. Every plan maintains a formulary, the list of covered medications, and formularies change annually. A drug can move to a pricier tier, acquire a new authorization requirement, or drop off the list entirely, and a drug that is not covered is not protected by any cap. The single highest-value task of open enrollment takes about twenty minutes: enter every medication you take into the official Medicare Plan Finder and look at the projected annual drug cost under each plan you are considering. Assumptions carried over from last year are how people end up standing at a pharmacy counter in February staring at a price that tripled over the holidays.
Networks move under your feet
An Advantage plan is a contract with a specific set of doctors and hospitals, and that set is not stable. Health systems and insurers renegotiate constantly, and when talks fail, a hospital group can exit a network mid-year. Your plan, meanwhile, is generally locked until the next enrollment period unless you qualify for a special exception. Care you get outside the network usually costs more, and in many plans it does not even count toward your out-of-pocket maximum, which means the ceiling you relied on quietly stops applying.
The exposure is worst in rural areas, where there may be one cardiologist within reasonable driving distance. If that one practice is out of network, the choice becomes a long drive or a full-price bill, and some people respond by skipping the appointment altogether, which is the most expensive option of all. Two calls protect you here. Before enrolling, call each doctor and facility you actually use and ask whether they expect to be in the specific plan's network next year; do the same for any hospital you would want in an emergency. Directories lag reality, and the front desk usually knows before the website does.
An honest comparison in one afternoon
The whole exercise fits in a few hours if you do it in order.
- Write down your real usage: every prescription with dosage, every doctor you saw this year, any procedure you know is coming.
- For each candidate plan, find the in-network MOOP in the plan documents. Treat it as the worst-case price of the year and ask whether you could absorb it without touching money you cannot replace.
- Run your drug list through the Plan Finder and compare projected annual totals, including the premium.
- Confirm your doctors and preferred hospital by phone, plan by plan.
- Add it up two ways: what the year costs if your health stays fine, and what it costs if it does not. Choose while looking at both numbers instead of the one in the largest font.
The television commercials that run all autumn are engineered to make this feel unnecessary, all gym memberships and dental allowances and urgent phone numbers. Extra benefits have real value for some people, and it is fine to count them, after the medical math, never in place of it. A free fitness membership does not offset a $9,000 hospital year.
If any part of this feels over your head, that is normal, and there is free, unconflicted help. Every state runs a State Health Insurance Assistance Program, reachable through shiphelp.org, where trained counselors who do not work for any insurer will sit with you and compare plans line by line at no charge. People who sell plans for a living are pleasant and often knowledgeable, and they are also paid by the answer you reach. For a decision that sets your financial exposure for an entire year of your health, an hour with someone who has no stake in the outcome is the cheapest insurance available. This is general information rather than personalized advice; plan details vary by county and change every year, so verify the numbers for the plans actually offered where you live before you enroll.
