Every autumn, roughly a third of the mail in America’s Medicare households is plan marketing. Almost none of it is useful, because none of it knows who your doctors are or what medication you take.
Meanwhile, one envelope that arrived in September — the one nobody opens — contains the only information that actually matters.
This is a guide to doing the Annual Enrollment Period properly: what changes, what to read, how to compare, and what to do if you miss it.
What AEP is, and what it is not
The Annual Enrollment Period runs from October 15 to December 7 every year. Changes made during it take effect on January 1.
What you can do during AEP:
- Join a Medicare Advantage plan for the first time
- Switch from one Medicare Advantage plan to another
- Drop a Medicare Advantage plan and return to Original Medicare
- Join a standalone Part D prescription drug plan
- Switch from one Part D plan to another
- Drop Part D coverage entirely (rarely a good idea — see the penalty section)
What AEP does not do:
It does not give you a right to buy a Medicare Supplement without medical underwriting. This is the most consequential misunderstanding of the whole window, and it catches people every year.
Leaving a Medicare Advantage plan during AEP is easy — you simply enroll in Original Medicare and a Part D plan. Buying a Medigap policy afterwards is a separate transaction governed by separate rules, and in most states the carrier may ask about your health history and decline you. (Massachusetts, Connecticut and a handful of other states are more generous — see our Massachusetts turning 65 guide.)
The asymmetry to plan around
Joining a Medicare Advantage plan is always possible. Buying a Medigap policy usually is not, once your six-month open enrollment window has closed and no guaranteed-issue right applies.
If you are considering leaving Advantage for Original Medicare and a supplement, get the supplement approved and in force before you drop anything. Never cancel first.
What actually changes on January 1
This is the part people do not expect. Nothing has to change in your life for your plan to become the wrong plan. The plan itself moves.
Every January 1, on every Medicare Advantage and Part D plan:
The formulary changes. Drugs are added, removed, or moved between tiers. A medication that was a preferred generic in December can be a non-preferred brand in January, at several times the copay.
Tier cost sharing changes. Even if your drug stays on the same tier, what that tier costs can change.
The provider network changes. Contracts with hospitals and physician groups are renegotiated annually. A practice that was in-network last year may not be this year — and the notice you receive about it is easy to miss.
Premiums, deductibles and the out-of-pocket maximum change. Sometimes by trivial amounts, sometimes not.
Utilization rules change. Prior authorisation requirements, step therapy and quantity limits are revisited annually.
Supplemental benefits change. Dental, vision, hearing and over-the-counter allowances are re-set. The dental benefit that drew you to a plan can be materially different next year.
All of this arrives in one document.
The Annual Notice of Change
Your carrier is required to send you an Annual Notice of Change (ANOC) each September, along with the following year’s Evidence of Coverage. It sets out, side by side, what your plan looked like this year and what it will look like next year.
It is the single most useful piece of mail you receive all year, and it is very easy to mistake for marketing.
How to read it in ten minutes:
- Go straight to the drug section. Find each of your medications. Check the tier for next year against the tier for this year. Any movement upward is the thing to investigate.
- Check the premium and deductible. Note both the direction and the size of any change.
- Check the out-of-pocket maximum. On an Advantage plan this is your worst-case number.
- Check the office visit and specialist copays. These drive your cost in a normal year.
- Check the inpatient hospital cost share. This drives your cost in a bad year.
- Skim the supplemental benefits. If a dental or hearing allowance was part of why you chose this plan, confirm it survived.
Then separately: verify your doctors. The ANOC will not list them. Call each practice and ask whether they will be in-network for your specific plan for the coming plan year, or check the plan’s provider directory for the new year rather than the current one.
How to compare plans properly
The single biggest error in AEP is comparing plans on premium. It is the most visible number and the least informative.
For Part D, compare total annual cost
A Part D plan has four moving parts: the monthly premium, the annual deductible, the copay or coinsurance for each drug, and the annual out-of-pocket cap.
Total annual cost is:
(monthly premium × 12) + deductible + the sum of your copays across the year, capped at the plan’s out-of-pocket maximum for covered drugs.
Consider two plans for the same person with the same prescriptions:
| Cost factor | Plan A | Plan B |
|---|---|---|
| Monthly premium | Low | Roughly three times Plan A |
| Annual deductible | Full deductible applies to all tiers | Waived on lower tiers |
| Your maintenance drug | Non-preferred tier | Preferred tier |
| Your specialty drug | Step therapy required first | On formulary, no step therapy |
| Your pharmacy | Standard, not preferred | Preferred |
| Where the cost lands | In copays, all year | In the premium, predictably |
| Total-cost winner | Only if you take very little | Usually, once you take several drugs |
Plan A wins on the mailer. Plan B frequently wins on the bank statement. There is no way to know which applies to you without running your own list.
Our Part D total cost estimator does this arithmetic for three plans at once. If you would rather not do it yourself, send us the list and we will run every plan in your county at no charge — that is what a drug cost review is.
For Medicare Advantage, compare the worst year
Build a simple two-column view for each candidate plan:
A normal year. Premium × 12, plus the copays you would realistically incur — a few primary care visits, a couple of specialist visits, your prescriptions, routine labs.
A bad year. Premium × 12, plus the out-of-pocket maximum. That is the ceiling, and it is the number that decides whether a plan is genuinely affordable.
A plan with a $0 premium and a high out-of-pocket maximum and a plan with a $0 premium and a low one look identical in an advertisement and are completely different products.
Then apply the two hard filters that eliminate candidates outright: are your doctors in the network, and are your prescriptions on the formulary at a tier you can afford. A plan that fails either is not a candidate, regardless of what else it offers.
The other windows, and how they differ
AEP is not the only opportunity, and knowing the others prevents a lot of unnecessary panic.
| Window | When | Who it is for | What it allows |
|---|---|---|---|
| Annual Enrollment Period | 15 Oct – 7 Dec | Everyone on Medicare | Any Advantage or Part D change |
| MA Open Enrollment | 1 Jan – 31 Mar | People already in an Advantage plan | One change: another Advantage plan, or back to Original Medicare |
| General Enrollment Period | 1 Jan – 31 Mar | People who missed their Part B enrollment | Enroll in Part B, with a possible penalty |
| Special Enrollment Periods | Triggered by an event | Anyone with a qualifying event | Enroll or change outside the standard windows |
| Medigap Open Enrollment | 6 months from Part B start | People new to Part B at 65+ | Buy any Medigap policy with no health questions |
The Medicare Advantage Open Enrollment Period is the safety valve most people do not know about. If you are in an Advantage plan on January 1, you get one change between January 1 and March 31. Enrolled in December, discovered in February that your specialist is not in the network? You have until March 31 to fix it.
It does not let someone on Original Medicare join an Advantage plan, and it does not create a Medigap guaranteed-issue right.
Special Enrollment Periods: the ones people miss
If you miss AEP entirely, do not assume you are stuck until next October. Common Special Enrollment Period triggers include:
- Moving to an address outside your plan’s service area, or into an area with different plan options
- Losing employer or union coverage
- Your plan leaving your county or ending its Medicare contract
- Entering or leaving a skilled nursing facility or long-term care institution
- Qualifying for Extra Help, Medicaid or a Medicare Savings Program
- Losing Extra Help or Medicaid eligibility
- A federally declared disaster or emergency affecting your area
- An enrollment error caused by a federal employee or plan representative
Most run two months from the qualifying event, and most require documentation. If anything has changed in your circumstances, ask — you may have a window open right now.
The penalties, and how they work
Two permanent penalties sit behind these windows, and both are avoidable.
The Part B late-enrollment penalty is 10 percent of the standard Part B premium for each full twelve-month period you were eligible for Part B and did not enroll, without creditable employer coverage. It is added to your premium for as long as you have Part B.
The Part D late-enrollment penalty applies if you go 63 days or more without creditable prescription drug coverage after your Initial Enrollment Period. It is calculated per uncovered month and, once attached, generally persists for as long as you have Part D coverage.
The Part D penalty catches a specific and entirely sympathetic group of people: those who take no medication at 65 and see no reason to buy drug coverage. Four years later they need a prescription, enroll, and discover a surcharge that will follow them for the rest of their life. If you take nothing today, the right move is usually the cheapest compliant plan in your area, held purely as insurance against the penalty.
Extra Help, and why so many people miss it
Extra Help — formally the Low Income Subsidy — reduces or eliminates Part D premiums, deductibles and copays for people within certain income and asset limits. The limits are considerably more generous than most people assume.
It is automatic if you have Medicaid, Supplemental Security Income or a Medicare Savings Program. Otherwise you have to apply, through Social Security. Enormous numbers of people who would qualify never do, for the entirely ordinary reason that nobody tells them it exists.
Separately, Medicare Savings Programs are state-administered and can pay your Part B premium, and depending on the program your deductibles and coinsurance too. Qualifying for one also confers automatic Extra Help.
We screen for both in every review. There is nothing in it for us — it is part of doing the job properly.
A practical AEP calendar
September. Your ANOC arrives. Keep it. Do not act yet — plan details for the coming year are published progressively through late September and early October.
Early October. Gather: the ANOC, your current plan card, your prescription list with strengths and quantities, and the list of doctors and facilities you want to keep.
Mid October. AEP opens on the 15th. Run your drug list against next year’s formularies. Verify each doctor for next plan year. Compare candidates on total cost.
November. Decide. If you are moving to a supplement, get it approved and in force before dropping anything.
By December 7. Submit. Get the effective date confirmed by the carrier, not just by an enrollment confirmation screen.
Late December. Confirm your new card arrived. Make sure your pharmacy has the new plan on file before January 1 — this prevents the classic bad morning at the counter.
January to March. If something is wrong and you are in an Advantage plan, you still have the MA Open Enrollment Period.
The phone call we would like to prevent
It comes every February and it always starts the same way: “I went to pick up my prescription and they wanted four hundred dollars.”
The drug moved tiers on January 1. The notice arrived in September. The window to change plans closed on December 7. And now the only routes available are a formulary exception request through the plan — which does work more often than people expect, with a prescriber’s support — or waiting until the following October.
The whole thing is prevented by twenty minutes in October.
How much of this you have to do yourself
None of it, if you do not want to.
An annual coverage review is exactly this exercise, done for you: we read the ANOC, re-run every prescription against next year’s formulary at your pharmacy, verify every doctor against next year’s network, compare against the other plans now available in your county, and give you a recommendation with the reasoning written down.
It costs nothing. Carriers pay licensed brokers a commission built into the premium, and for Medicare products those commissions are capped by federal regulation — which is precisely why we can afford to tell you, as we frequently do, that your current plan is still the right one and you should do nothing.
Even if you did not enroll through us, bring your ANOC. If the answer is stay put, we will tell you that too.
What to do next
- Work out where you stand with the Part D total cost estimator
- Read up on Medicare Advantage and Medicare Supplement if you are reconsidering the structure
- Put a note in your calendar for the first week of October
- Or just call us — (800) 657-4213 — and we will take it from there
Frequently asked questions
When is the Medicare Annual Enrollment Period?
From October 15 to December 7 every year, with any changes taking effect on January 1. It applies to Medicare Advantage plans and standalone Part D prescription drug plans.
What can I change during AEP?
You can join a Medicare Advantage plan, switch between Advantage plans, drop an Advantage plan and return to Original Medicare, or join, switch or drop a standalone Part D plan. You cannot use AEP to buy a Medigap policy without underwriting.
Do I have to do anything if I want to keep my plan?
Administratively, no — plans auto-renew if they still exist. The risk is not administrative. The plan you are auto-renewed into on January 1 is not the plan you signed up for: the formulary, tiers, network, premium and cost sharing all reset. Reviewing it is the point.
What happens if I miss the deadline?
If you are already in a Medicare Advantage plan you get one more change during the Medicare Advantage Open Enrollment Period from January 1 to March 31. Otherwise you generally wait for the following AEP unless a Special Enrollment Period applies — moving, losing employer coverage, qualifying for Extra Help and several others.
Does switching plans cost anything?
No. There is no fee to switch, and no fee to use a licensed broker to help. Premiums are filed with regulators and are identical whether you enroll on your own or through a broker.