7 Mistakes to Avoid During This Annual Enrollment Period (AEP)

Every October, a familiar collection of envelopes begins arriving in the mailboxes of Americans with Medicare. Some contain important notices about changes to existing coverage. Others advertise plans with lower premiums, dental benefits, or additional services. The offers can sound appealing, particularly to retirees trying to manage healthcare expenses on a fixed income. Yet the most important information is often found not in the largest print, but in the details that explain what a plan will actually cover.

From October 15 through December 7, 2026, people with Medicare can make certain changes to their health and prescription drug coverage for 2027. The choices made during this period can affect which doctors they see, how much they pay for medications, and what happens when they need hospital care. Seven common mistakes deserve particular attention because they can turn an otherwise reasonable coverage decision into an expensive or inconvenient one. Avoiding them begins with understanding that the best Medicare plan is not necessarily the one with the most benefits, but the one that fits a person's healthcare needs and financial circumstances.

Mistake 1: Assuming Your Current Plan Will Remain the Same

For someone who has been happy with their Medicare coverage, doing nothing during Annual Enrollment may seem sensible. Their doctor accepts the insurance, prescriptions are affordable, and the plan has caused few problems. Unfortunately, Medicare Advantage and Part D prescription drug plans can change from one year to the next. Premiums, deductibles, copayments, covered medications, provider networks, and additional benefits may all be different when the new coverage year begins.

Insurance companies generally send members an Annual Notice of Change explaining important adjustments for the following year. This document deserves careful attention, even when the plan's name remains familiar. A medication that previously carried a modest copayment could move into a more expensive cost category, or a preferred pharmacy might no longer offer the same pricing. Someone who overlooks these changes may not discover their consequences until visiting a doctor or filling a prescription in January.

The goal of reviewing an existing plan is not necessarily to replace it. Staying enrolled can be an excellent decision when coverage continues to meet a person's needs. However, that decision should follow a comparison of the coming year's benefits, costs, and provider access. Medicare's annual enrollment process gives beneficiaries an opportunity to reconsider their coverage, not an obligation to change it.

Mistake 2: Choosing a Plan Based on the Monthly Premium Alone

A Medicare Advantage plan advertising a $0 monthly plan premium can be attractive, especially for someone managing expenses during retirement. But a low premium does not mean that medical care will be free. Beneficiaries generally must continue paying their Medicare Part B premium, and the plan may charge deductibles, copayments, or coinsurance when services are used. Those expenses can become significant when someone needs frequent specialist visits, outpatient treatment, or hospital care.

Consider two hypothetical Medicare Advantage plans. One has no additional monthly premium but charges higher amounts for certain medical services. Another requires a monthly premium but offers lower costs for some types of care. A healthy person who rarely visits doctors might prefer the first arrangement, while someone receiving regular treatment could find the second more affordable overall. Neither plan is automatically better because the answer depends on how much care a person expects to use.

Medicare Advantage plans have an annual out-of-pocket limit for covered Part A and Part B services, although the amount varies by plan. Original Medicare generally has no comparable annual limit unless a beneficiary has other coverage that helps pay those expenses. A meaningful comparison therefore considers the full financial picture, including monthly premiums, expected medical expenses, prescription costs, and the possibility of unexpected illness. The lowest advertised price is not always the lowest annual cost.

Mistake 3: Failing to Verify Doctors, Hospitals, and Specialists

People often choose healthcare providers because they trust them. A primary care physician may have treated someone for years, while a specialist may understand a complicated medical history that would take time to explain to another doctor. Losing access to those providers can disrupt care, particularly for individuals managing chronic illnesses. That makes provider participation one of the most important details to verify before enrolling in a Medicare Advantage plan.

Many Medicare Advantage plans use provider networks. Health Maintenance Organization plans, commonly called HMOs, generally require members to use network providers for nonemergency care, subject to certain exceptions. Preferred Provider Organization plans, or PPOs, usually provide more flexibility to receive covered services outside the network, although members may pay more. These arrangements can offer useful coverage, but they operate differently from Original Medicare, which generally allows beneficiaries to see any provider who accepts Medicare.

A physician's participation in one insurance company's network does not necessarily mean that the physician accepts every plan offered by that company. Networks can also change between coverage years. Before enrolling, beneficiaries should verify their preferred doctors, hospitals, and specialists against the specific plan being considered. When an established medical relationship is particularly important, confirming participation directly with both the provider and the plan can help prevent an unwelcome surprise.

Mistake 4: Overlooking Changes to Prescription Drug Coverage

For someone taking several medications, prescription coverage can be one of the largest differences between Medicare plans. Two plans with similar premiums may produce very different pharmacy expenses because they cover drugs differently. Medicare Part D plans maintain formularies, which are lists of covered medications, and organize many drugs into cost categories. Plans may also impose requirements such as prior authorization, quantity limits, or step therapy before covering certain prescriptions.

Imagine a retiree who takes medication for diabetes, high blood pressure, and a heart condition. Their current plan may cover all three prescriptions at manageable costs, while another plan offers a lower premium but places one medication in a more expensive category. The second plan could appear cheaper during enrollment yet cost more over the year. Pharmacy choice can also matter because plans may offer different pricing at preferred and standard network pharmacies.

Medicare's prescription drug program includes important protections against high covered drug expenses, but those protections do not make every plan identical. Formularies, pharmacy networks, coverage restrictions, and individual drug costs still deserve review. Beneficiaries should compare their actual medications, including dosage and quantity, rather than relying on general descriptions of prescription benefits. For people with ongoing medical conditions, this review can be as important as checking the doctors who provide their care.

Mistake 5: Giving Up Medigap Coverage Without Understanding the Consequences

One of the most consequential enrollment decisions involves moving from Original Medicare with a Medicare Supplement Insurance policy, commonly called Medigap, into Medicare Advantage. Medigap policies help pay certain expenses that Original Medicare does not cover, such as deductibles and coinsurance. Medicare Advantage offers a different approach, often combining hospital, medical, and prescription coverage with additional benefits. Both arrangements can work well, but changing between them requires careful consideration.

The difficulty arises when someone decides to return to Original Medicare after leaving a Medigap policy. Federal rules generally provide a six-month Medigap Open Enrollment Period beginning when a person is both 65 or older and enrolled in Medicare Part B. During that period, insurance companies generally cannot deny a Medigap policy or charge more because of health conditions. Outside that window, obtaining supplemental coverage may be more difficult unless a guaranteed-issue right or additional state protection applies.

Suppose a retiree drops Medigap to join a Medicare Advantage plan offering attractive dental benefits. Two years later, they decide they would prefer Original Medicare again. Although the fall enrollment period generally allows them to leave Medicare Advantage, it does not automatically guarantee that they can purchase another Medigap policy. Certain trial rights may protect people in specific circumstances, but those protections have conditions and time limits. Understanding these consequences before surrendering existing coverage can preserve important choices for the future.

Mistake 6: Overlooking Financial Assistance That Could Lower Medicare Costs

Many older adults assume that financial assistance with Medicare is available only to people with extremely limited income. Others have heard of assistance programs but never investigated whether they qualify. As a result, some beneficiaries may pay more than necessary for premiums, prescription drugs, or other healthcare expenses. Eligibility depends on income, resources, household circumstances, and the rules of the particular program.

Medicare Savings Programs, administered through state Medicaid agencies, can help eligible beneficiaries pay certain Medicare expenses. Depending on the program, assistance may cover the Part B premium and, for some individuals, additional Medicare cost-sharing. The Extra Help program provides assistance with Medicare Part D prescription drug costs for people who meet its eligibility requirements. These programs can make a meaningful difference for someone who relies on Social Security or has limited retirement income.

Consider a widow who has continued paying her Medicare premiums and prescription costs without realizing that she might qualify for assistance. A review of her finances could reveal eligibility for a program that reduces those expenses. Even when someone has been found ineligible before, changes in income, household circumstances, or program limits may justify another review. Annual Enrollment is an opportunity to examine coverage costs, but it can also be a useful reminder to investigate assistance that may be available throughout the year.

Mistake 7: Waiting Until the Last Minute or Assuming Changes Can Be Made Anytime

The Annual Enrollment Period lasts several weeks, which can create a false sense of urgency being unnecessary. October passes quickly, however, and the weeks leading into December are often filled with family obligations, travel, and holiday preparations. Comparing plans may require checking medications, contacting physicians, reviewing benefit documents, and asking questions about unfamiliar coverage rules. A decision made under deadline pressure may overlook details that would have been apparent with more time.

For the 2026 enrollment season, Medicare beneficiaries can begin comparing 2027 plan options on October 1. The Annual Enrollment Period runs from October 15 through December 7, and changes made during that period generally take effect January 1, 2027. People can join, switch, or drop eligible Medicare Advantage and prescription drug plans during this window. Waiting until the final days may leave little time to resolve questions about doctors, pharmacies, or enrollment paperwork.

Some beneficiaries assume they can simply change plans again if their January coverage proves disappointing. Medicare does provide a Medicare Advantage Open Enrollment Period from January 1 through March 31 for people already enrolled in Medicare Advantage. During that period, eligible members can make one permitted change, such as switching to another Medicare Advantage plan or returning to Original Medicare. However, it does not provide the same options to everyone, and it does not automatically restore Medigap protections. Other changes generally require a qualifying Special Enrollment Period or another applicable enrollment opportunity.

Making a Medicare Decision That Holds Up Beyond Enrollment

The seven mistakes share a common theme: Medicare coverage should be evaluated according to how it works in everyday life, not simply how it appears in advertisements or enrollment materials. A plan's premium matters, but so do prescription costs, physician access, hospital coverage, financial protections, and the flexibility to respond when healthcare needs change. The most useful comparison considers these factors together, recognizing that a benefit attractive to one person may offer little value to another.

For many beneficiaries, a careful review will confirm that their existing plan remains a good choice. Others may discover that changes in their health, finances, or insurance benefits make a different arrangement more appropriate. Neither outcome should be treated as a victory or a disappointment. The purpose of Annual Enrollment is to make an informed decision about coverage for the coming year while understanding the possible consequences for the years that follow.

Beacon Senior Health Advisors helps individuals and families review Medicare coverage, understand their options, and consider how plan differences may affect their personal circumstances. Whether you are satisfied with your current coverage or considering a change, an informed review can provide greater confidence before the December deadline. To discuss how these seven considerations apply to your situation, schedule a free consultation with Beacon Senior Health Advisors.

References and Further Reading

Centers for Medicare & Medicaid Services. Medicare & You 2027: The Official U.S. Government Medicare Handbook. Relevant sections include page 13 for the 2026 Annual Enrollment dates and 2027 coverage changes; pages 61–75 for Medicare Advantage coverage and enrollment rules; pages 79–82 for Medicare Supplement Insurance; and pages 83–94 for prescription drug coverage.

Medicare & You: Official Medicare Handbook

Compare Medicare Plans

Medicare Savings Programs

Extra Help With Medicare Prescription Drug Costs

Medicare Supplement Insurance (Medigap)

Educational disclaimer: This article provides general information about Medicare and is not a guarantee of benefits, costs, eligibility, or enrollment rights. Medicare plans, provider networks, financial assistance eligibility, and state insurance protections vary by location and individual circumstances. Readers should review official plan documents and Medicare resources before making coverage decisions. Beacon Senior Health Advisors is not affiliated with or endorsed by the U.S. government or the federal Medicare program.

Written by Malachi Ulysse
Founder & Advisor, Beacon Senior Health Advisors
Licensed Insurance Broker Since 2019