Medicare Open Enrollment Mistakes Seniors Must Avoid

Introduction: Don’t Let Open Enrollment Catch You Off Guard

Every fall, millions of seniors face one of the most important — and most confusing — windows of the year: Medicare Open Enrollment. Running from October 15 through December 7, this is your one chance to review, switch, or update your Medicare coverage for the coming year.

According to a 2023 study by the Kaiser Family Foundation, only about 10% of Medicare beneficiaries compare their plan options during Open Enrollment each year. That means the vast majority are sticking with plans that may no longer serve them well — plans with higher costs, dropped medications, or fewer providers.

1. Assuming Your Current Plan Hasn’t Changed

This is the single most common — and most costly — mistake seniors make. Medicare Advantage and Part D plans can change their premiums, copays, formularies, and provider networks every January 1.

Insurance companies are required to send you an Annual Notice of Change (ANOC) by September 30 each year. Open and carefully read your ANOC letter as soon as it arrives. Pay special attention to changes in monthly premiums, drug costs, deductibles, and provider networks.

2. Not Reviewing Your Prescription Drug Coverage

According to CMS, Part D formularies change an average of 15–20% from year to year. The average Medicare beneficiary takes 4 to 5 prescription drugs — those changes can significantly impact your total annual drug costs.

Make a complete list of every medication you take and use the Medicare Plan Finder at Medicare.gov to compare Part D plans. For a step-by-step walkthrough, download our free Medicare checklist.

3. Overlooking the Difference Between Original Medicare and Medicare Advantage

Many seniors choose a plan based on a TV commercial or a neighbor’s recommendation without comparing the specifics. Key questions to ask yourself:

• Do I travel frequently or split time between two states? (Original Medicare may be better.)
• Do I want dental, vision, and hearing benefits bundled in? (Many Advantage plans offer this.)
• Am I comfortable with network restrictions and referral requirements?
• Can I afford a Medigap supplemental policy if I choose Original Medicare?

4. Missing the Enrollment Deadline Entirely

The Medicare Open Enrollment period is October 15 through December 7 — no exceptions, no extensions. A 2022 survey found that nearly 1 in 4 Medicare-eligible adults weren’t confident about when Open Enrollment starts or ends.

Mark October 15 and December 7 on your calendar right now. Don’t wait until the last week — hold times increase near the deadline.

5. Ignoring Extra Benefits and Savings Programs

Many seniors don’t realize they may qualify for programs that can dramatically reduce their Medicare costs:

• Medicare Savings Programs (MSPs): Can pay your Part B premiums, deductibles, and copays.
• Extra Help (Low-Income Subsidy): Worth an average of $5,300 per year, according to CMS.
• Medicare Advantage supplemental benefits: Grocery allowances, transportation, over-the-counter health product credits.

6. Making Decisions Based on Premium Alone

A plan with a $0 premium might have high copays for specialist visits, expensive drug tiers, or a narrow network. What actually matters is your total annual cost of care, which includes monthly premiums, deductibles, copays, coinsurance, prescription drug costs, and out-of-pocket maximum.

For more guidance, explore our Medicare resources.

A Quick-Reference Checklist for Open Enrollment

1. Read your Annual Notice of Change letter carefully.
2. Review your current prescriptions against next year’s formulary.
3. Confirm your doctors and pharmacies are still in-network.
4. Compare at least 3 plans using the Medicare Plan Finder at Medicare.gov.
5. Check your eligibility for Extra Help and Medicare Savings Programs.
6. Calculate total annual costs — not just monthly premiums.
7. Enroll in your chosen plan before December 7.