Every fall, an envelope arrives that determines what millions of Americans will pay for health care and prescriptions the following year, and most of them never open it. It is the Annual Notice of Change, or ANOC, and if you are in a Medicare Advantage plan or a Part D drug plan, your insurer must deliver yours by September 30. Everything in it takes effect January 1. Medicare describes the mailing on its upcoming plan changes page.
Here is why this document matters more than almost anything else in your mailbox: your plan can change substantially from one year to the next, and if you do nothing, you are automatically renewed into the new version, whatever it now costs and covers. The ANOC is your one clean warning. This year, when yours arrives in September, here is exactly what to read, in order of how badly it can hurt you.
1. The premium and the deductibles
The ANOC opens with a side-by-side table: this year’s costs next to next year’s. Check the monthly premium first, then the deductibles, medical and drug separately if your plan has both. A premium that jumps is annoying but visible; a deductible that doubles is quieter and can cost you more. Remember that a $0 premium tells you nothing by itself. Plans can hold the premium flat while raising copays and tightening coverage everywhere else, which is precisely why the rest of the document exists.
2. The drug formulary, where the expensive surprises live
For most people, this is the section that changes the math. Pull out your prescription list and check every drug against next year’s formulary changes. Three things can happen to a medication: it can be dropped from coverage entirely, it can move to a higher tier with a bigger copay, or it can pick up new requirements such as prior authorization or step therapy, which means trying a cheaper drug first. Any one of those on a medication you take daily can swing your annual costs by hundreds of dollars. The 2026 cap on out-of-pocket drug spending limits the worst-case damage, but only for drugs your plan actually covers; a dropped drug sits outside the cap entirely.
3. Provider and pharmacy networks
Next, confirm that your doctors, your hospital, and your pharmacy are still in-network for next year. Networks shift every year, and an out-of-network doctor can mean higher costs or, in an HMO, no coverage at all. The ANOC will flag network changes in general terms; for your specific doctors, call their office or the plan and ask directly. Do the same for your pharmacy, because preferred-pharmacy lists change too, and the same prescription can carry a very different copay across the street.
4. The out-of-pocket maximum and the extras
For Medicare Advantage members, the plan’s annual out-of-pocket maximum is your true worst-case number for medical care, so note whether it rose. Then glance at the extra benefits: dental, vision, hearing, transportation, gym memberships. Plans adjust these freely, and the extras that attracted you two years ago may have quietly shrunk. Weigh them honestly; a generous dental allowance does not offset a formulary change that costs you more every single month.
5. The service area, the fine print that can end your plan
Occasionally the ANOC, or a companion notice, announces that your plan is leaving your county or shutting down altogether. If that happens, you get special rights to choose new coverage, and in some cases a guaranteed opportunity to buy a Medigap policy without medical underwriting. Do not shrug this letter off; those special rights come with deadlines.
What to do if you do not like what you read
The timing of the ANOC is not an accident. It lands just before Medicare Open Enrollment, which runs October 15 through December 7 every year. During that window you can switch Medicare Advantage plans, move between Original Medicare and Medicare Advantage, or change drug plans, with the new coverage starting January 1. The comparison tool at medicare.gov/plan-compare lets you enter your actual medications and doctors and see real costs across every plan in your ZIP code. And if you make a choice you regret, Medicare Advantage members get one more chance: from January 1 through March 31, you can make a single switch to another Advantage plan or back to Original Medicare.
If the document feels like homework, you do not have to do it alone. Every state runs a State Health Insurance Assistance Program, known as SHIP, offering free one-on-one counseling from trained volunteers who have no plan to sell you; find yours through shiphelp.org or by calling 1-800-MEDICARE.
Fifteen minutes with the ANOC in September, a comparison in October if anything looks worse, and you are done until next fall. The people who get burned by plan changes are almost never the ones who read the envelope. Put it on the calendar now: when the notice arrives this September, open it the same week, list in hand.
