Medicare Open Enrollment 2026: 7 Mistakes You're Making with Your Plan Review (and How to Fix Them)

Medicare’s Annual Enrollment Period runs October 15 through December 7, 2026. It’s your chance to review your coverage and make certain changes for 2027. If you make a change during this period, it generally takes effect January 1, 2027. Your plan must receive your enrollment request by December 7. Medicare explains the enrollment period and your options here.

A plan that worked well this year may still be right for you, but check before assuming. Here are seven common plan-review mistakes and practical ways to avoid them.

A note about this guide: This is general Medicare education, not a personalized plan recommendation. Plan availability and costs vary. Confirm current details with Medicare, the plan, and your providers, and consider speaking with a licensed Medicare advisor about your situation.

1. Assuming your plan will stay the same

Plans can change their premiums, cost-sharing, benefits, provider networks, and prescription coverage from year to year. Even if you don’t make a change, your current plan’s 2027 terms may differ from this year’s.

How to fix it: Read your plan’s Annual Notice of Change (ANOC). It outlines changes that take effect in January. Compare it with the coverage you expect to need next year. If the notice hasn’t arrived, contact your plan. Medicare’s ANOC guidance explains what to look for.

2. Choosing by monthly premium alone

A low monthly premium doesn’t tell you what your care may cost over the year. Deductibles, copayments, coinsurance, prescription costs, and, for Medicare Advantage, your plan’s out-of-pocket maximum can all matter. A plan with a higher premium may fit some people better; the right comparison depends on your needs and the plan details.

How to fix it: Compare estimated total costs, not just premiums. Include the care and prescriptions you expect to use, and check what you could owe if you need more services than usual. Use Medicare Plan Compare as a starting point, then verify details with the plan.

3. Forgetting to check every prescription

A prescription covered this year may have different coverage or costs next year. Plans may use different formularies, their lists of covered drugs, and may set rules such as prior authorization, step therapy, or quantity limits. Your pharmacy choice can also affect what you pay.

How to fix it: Make a current list of your medicines, including the dose and how often you take each one. For each plan you’re considering, check the 2027 formulary, any restrictions, the drug’s cost, and whether your pharmacy is in-network or preferred. Confirm the information with the plan. Learn more about how Medicare drug plans work.

4. Assuming your doctors are in the network

If you have Medicare Advantage, a doctor or hospital that accepts your current plan may not participate in another plan, or may leave a network for next year. Provider access and costs can vary by plan.

How to fix it: Write down the doctors, specialists, hospitals, and other providers you want to keep. Check each one in the directory for the specific 2027 plan, then confirm directly with both the provider’s office and the plan. Don’t rely on last year’s directory or an informal assurance.

5. Overlooking how you use care and the plan’s rules

Plan extras (such as dental, vision, hearing, fitness, or over-the-counter benefits) can be useful, but they’re only part of the picture. You’ll also want to understand how you access care. Medicare Advantage plans may have network, referral, or prior-authorization rules. Original Medicare has different coverage arrangements, and you may need to consider separate Part D coverage and, if appropriate, Medigap.

How to fix it: Think through your typical care: preferred providers, travel, prescriptions, and services you expect to use. Then compare how each plan handles those needs, including referral requirements, prior authorization, and the limits or conditions on extra benefits. If you’re considering a move from Medicare Advantage to Original Medicare, check whether you can buy Medigap and when. Medicare explains Medigap enrollment periods and rights.

6. Misunderstanding what you can change, and when

During the October 15–December 7 Annual Enrollment Period, you can make certain changes, including switching Medicare Advantage plans, changing Part D plans if you have Original Medicare, or moving between Original Medicare and Medicare Advantage. The right options depend on your current coverage.

Some people hear about a January enrollment period and assume it’s open to everyone for every type of change. The Medicare Advantage Open Enrollment Period, January 1–March 31, is generally for people already enrolled in Medicare Advantage. It allows one change: switch to another Medicare Advantage plan or return to Original Medicare. It isn’t a general second chance for everyone to change Part D plans or join Medicare Advantage.

How to fix it: Confirm that the change you want is allowed for your current coverage and enrollment period. If you’re considering leaving Medicare Advantage, check Medigap eligibility and timing before making a decision. See Medicare’s guide to Medicare Advantage and drug plan enrollment periods.

7. Making a decision before verifying the details

Online comparisons, mailers, and recommendations from friends can help you identify options, but they may not reflect your prescriptions, providers, or circumstances. Plan details can be easy to misread, and a search result is not a substitute for confirmation.

How to fix it: Before enrolling, verify the specific plan’s 2027 costs, drug coverage, pharmacy access, provider network, and rules. Keep notes on what you checked and save your enrollment confirmation. If you need help understanding your choices, ask questions before you submit a request.

A simple review checklist

Before December 7, set aside time to:

• Read your Annual Notice of Change.
• List your prescriptions, doctors, pharmacies, and expected care.
• Compare plan costs and coverage using your ZIP code.
• Confirm important details directly with the plan and providers.
• Check that your preferred change is available to you during this enrollment period.
• Submit any enrollment request by December 7, 2026, and keep the confirmation.

You don’t have to sort through every Medicare term by yourself. Maria Perryman is a Licensed Medicare Advisor who helps people 65+ understand their choices in plain language. Explore Medicare guidance and ways to work with Maria, or reach out with your questions. Your circumstances are unique, so take the time to verify the details that matter to you.