Every year between October 15 and December 7, Medicare runs its Annual Enrollment Period. During those seven weeks anyone with Medicare can change how they receive it: switch from one Part D drug plan to another, move between Medicare Advantage plans, leave Medicare Advantage for Original Medicare, or join Medicare Advantage for the first time. Whatever you choose takes effect on January 1.
Most people do nothing. That is understandable, because if you take no action your current plan generally renews on its own, and changing plans sounds like work with a risk attached. The problem is that a plan that renews is not a plan that stays the same. Premiums, deductibles, the list of covered drugs, the pharmacies in the preferred network and the doctors in the provider network can all change from one calendar year to the next, and the plan is only obliged to tell you, not to ask you.
This guide covers what to look at, in what order, and the one decision in this window that can be hard to undo.
The Letter That Already Arrived
By the end of September, every Medicare Advantage and Part D plan is required to send its members an Annual Notice of Change, usually shortened to ANOC. It sets out what will be different about the same plan next year. It often arrives in an envelope that looks like marketing and gets put aside.
Find it and read it before October 15. It answers the question that matters most, which is not “is there a better plan” but “is my current plan still the plan I think it is”. The sections worth reading closely:
- Premium and deductible for next year, compared with this year.
- The drug list, called the formulary. A drug you take can be dropped, moved to a more expensive tier, or given new restrictions such as prior authorisation or step therapy.
- Pharmacy network changes. A pharmacy that was preferred this year can become standard or out of network next year, which changes what you pay for the same prescription.
- Provider network changes, for Medicare Advantage. Doctors, medical groups and hospitals leave and join networks at the turn of the year.
- Extra benefits such as dental, vision and hearing allowances in Medicare Advantage plans, which are among the items most likely to change.
If you cannot find the notice, call the plan and ask for it, or look it up on the plan’s website. You are entitled to it.
Five Things Worth Checking
1. Every drug you take, by name and dose
Enter your actual prescriptions, including dose and quantity, into the Medicare Plan Finder at Medicare.gov. It compares the total estimated yearly cost across the plans available where you live, not just the premium. A plan with the lowest premium can be the most expensive plan once the drugs are counted, and the Plan Finder is the fastest way to see that.
Since the Inflation Reduction Act, Part D has an annual cap on out-of-pocket drug spending, set at $2,000 for 2025 and adjusted each year after that. Once you reach the cap, covered drugs cost nothing further for the rest of the year. The cap applies across every Part D plan, but how quickly you reach it, and what you pay on the way, still differs from plan to plan.
If large drug costs tend to land early in the year, the Medicare Prescription Payment Plan lets you spread your out-of-pocket drug costs across monthly payments instead of paying at the pharmacy counter. It does not lower the total, and it is not the right choice for everyone, but for someone on a fixed monthly income it can prevent a January bill that cannot be paid.
2. Your doctors and your hospital
For Medicare Advantage, look up each doctor you see regularly and the hospital you would want to go to, in the plan’s provider directory for next year, not this year. Then call the doctor’s office and ask whether they expect to be in that plan’s network next year. Directories are not always current, and the office usually knows before the directory is updated.
Original Medicare has no network. Any provider in the country that accepts Medicare will take it. That is one of the main reasons people move back to it, and it is also why the Medigap question below matters so much.
3. Your pharmacy
Check that the pharmacy you actually use is in network, and ideally preferred, for the plan you are considering. Mail-order pricing is often lower and is worth comparing for regular long-term medication.
4. Whether you qualify for Extra Help
Extra Help, also called the Low-Income Subsidy, lowers Part D premiums, deductibles and copays. Since 2024, eligibility has extended to people with incomes up to 150 percent of the federal poverty level, subject to a resource limit. Many people who qualify have never applied, and qualifying also opens additional chances to change plans during the year. Apply through Social Security, online or by phone. People who have Medi-Cal, or who are in a Medicare Savings Program, generally receive Extra Help automatically. Our guide to Medicare Savings Programs explains how QMB, SLMB and QI can also pay the Part B premium.
5. What the extras are really worth
Medicare Advantage plans often advertise dental, vision, hearing, fitness or grocery allowances. They can be real value. They can also be narrow: a dental benefit that covers two cleanings and little else, an allowance usable only at particular retailers, a hearing benefit limited to one supplier. Read the evidence of coverage for any extra that is the reason you are choosing a plan, and weigh it against the network and drug costs, which usually matter more.
The Decision That Is Hard to Reverse
Moving between Part D plans, or from one Medicare Advantage plan to another, is a decision you can revisit next autumn. Moving from Medicare Advantage back to Original Medicare is different, because of what happens to supplemental coverage.
Original Medicare on its own leaves you with a 20 percent share of most Part B costs and no annual out-of-pocket limit. Most people who rely on Original Medicare pair it with a Medicare Supplement policy, known as Medigap, which fills most of that gap. The difficulty is that outside certain protected windows, a Medigap insurer can ask health questions and can decline to sell you a policy, or charge more, because of your health.
Protected windows include your initial Medigap enrollment period when you first have Part B at 65 or older, and a trial right if you joined a Medicare Advantage plan for the first time and leave it within the first 12 months. Other federal and California guaranteed-issue rights apply when a plan leaves your area or ends its contract.
California adds a protection that is worth knowing about: under what is usually called the Medigap birthday rule, a person who already has a Medigap policy can switch to another policy with the same or fewer benefits during a window beginning on their birthday each year, without medical underwriting. It helps people who already have Medigap and want a cheaper equivalent policy. It does not help someone moving from Medicare Advantage who has no Medigap policy to switch from.
So before leaving Medicare Advantage for Original Medicare, confirm in writing whether you can get a Medigap policy and at what price. If you cannot, Original Medicare without a supplement may leave you exposed to large bills. This is exactly the kind of question the free HICAP counsellors described below answer every day.
If You Have Both Medicare and Medi-Cal
People who have both, often called dual eligibles or “Medi-Medi”, sit under a somewhat different set of rules.
Medi-Cal continues to cover what Medicare does not, and In-Home Supportive Services is a Medi-Cal benefit. Your choice of Medicare plan does not change your IHSS hours or your IHSS provider. Our guide to how IHSS and Medicare work together goes through the division of labour in detail.
In many California counties, dual eligibles can join a Medicare Medi-Cal Plan, sometimes called a Medi-Medi Plan, which coordinates both programmes under one organisation, with one card and one set of care coordinators. Where they are available, they can simplify life considerably for someone juggling many providers. Availability depends on county.
People with Medi-Cal or Extra Help also have more chances to change during the year than other Medicare beneficiaries. Since 2025, a special enrollment period allows limited changes on a monthly basis, including moving to Original Medicare with a standalone drug plan, or into an integrated plan for dual eligibles. The rules on exactly which moves are allowed are detailed and change from time to time, so confirm the current position with HICAP or Medicare before relying on it.
One practical point: staying on Medi-Cal depends on completing the annual renewal. Losing Medi-Cal can also mean losing Extra Help and a Medicare Savings Program, which raises Medicare costs overnight. Our guide to the Medi-Cal renewal packet explains the deadlines.
Other Windows Outside the Autumn
The October to December window is not the only chance.
- Medicare Advantage Open Enrollment, January 1 to March 31. If you are in a Medicare Advantage plan on January 1, you can make one change during this period: switch to a different Medicare Advantage plan, or leave for Original Medicare and join a standalone drug plan. It is a useful safety net if the plan you chose in the autumn turns out to be wrong in January.
- Special enrollment periods apply after certain events, such as moving out of a plan’s service area, moving into or out of a nursing home, losing other coverage, or a plan ending its contract with Medicare.
- Five-star plans. Medicare allows people to switch into a plan rated five stars at most points in the year, where one is available in their area.
Guarding Against Sales Pressure
The autumn is also the season of television advertisements, direct mail that looks official, and phone calls. A few rules protect you.
Medicare does not call people to sell plans. A caller who says they are “from Medicare” and wants to confirm your Medicare number or talk about new benefits should be treated as a scam until proven otherwise. Hang up and call Medicare directly.
Agents and brokers may not make unsolicited calls to sell Medicare plans, and may not visit your home uninvited. If you asked for a call, the agent can discuss only what you agreed to discuss.
An agent is usually paid by the plan they sign you into. That does not make their advice wrong, but it is a reason to check any recommendation against the Plan Finder or with a counsellor who has no commission at stake.
Never give your Medicare number, Social Security number or bank details to someone who contacted you. Medicare fraud frequently starts with a number handed over on a call like this.
Free, Unbiased Help in California
The Health Insurance Counseling and Advocacy Program, HICAP, provides free, confidential Medicare counselling in every California county. HICAP counsellors are trained, do not sell insurance and do not earn commission. They can compare plans against your drug list and doctors, explain Medigap options, check whether you qualify for Extra Help or a Medicare Savings Program, and help with appeals. Call 1-800-434-0222 to reach the local office. Demand is heavy in November, so booking in October is sensible.
HICAP is usually run through your local Area Agency on Aging, which also runs respite, meals and caregiver support. Our guide to your Area Agency on Aging explains what else it offers.
You can also call 1-800-MEDICARE directly, or use the Plan Finder at Medicare.gov yourself.
A Short Checklist for October
- Find the Annual Notice of Change and read the premium, drug list, pharmacy and network sections.
- Write down every medicine with its dose, every doctor you see, and your pharmacy.
- Run the list through the Medicare Plan Finder, or book a HICAP appointment and take the list with you.
- If you are considering leaving Medicare Advantage for Original Medicare, confirm Medigap availability and price in writing first.
- Check whether you qualify for Extra Help or a Medicare Savings Program, and apply if so.
- If you change, make the change before December 7 and keep the confirmation number.
- Watch the post in January for the new card and welcome materials, and check your first prescription fill at the pharmacy.
The Short Version
Your plan will probably renew on its own, but it may not be the same plan. Read the Annual Notice of Change, compare your actual drugs and doctors rather than premiums alone, and treat a move from Medicare Advantage back to Original Medicare as a decision that needs a Medigap answer first. If you have Medi-Cal as well, your IHSS is not affected by the Medicare choice, and you have more chances to change during the year. Free, commission-free help is available through HICAP in every county, and it is worth booking before the November rush.
This guide is general information, not individual advice. Plan details, dates and thresholds are set by Medicare and can change; confirm the current rules with Medicare or HICAP before acting.