Medicare Open Enrollment runs every year from October 15 through December 7. During this window, you can switch Medicare Advantage plans, change or drop your Part D prescription drug coverage, or move between Original Medicare and Medicare Advantage. Any changes you make take effect January 1 of the following year, so this is your annual opportunity to adjust your coverage based on changes in your health, finances, or the plans themselves.

What is Medicare Open Enrollment?

Medicare Open Enrollment is a federally mandated period when all Medicare beneficiaries can review and change their coverage without needing a qualifying event. According to the Centers for Medicare & Medicaid Services, this is the primary enrollment window for making voluntary changes to Medicare Advantage (Part C) and Medicare Part D prescription drug plans (CMS, 2026).

If you have Original Medicare (Parts A and B), you can add, drop, or switch Part D prescription drug plans. If you are enrolled in a Medicare Advantage plan, you can switch to a different Medicare Advantage plan, return to Original Medicare, or add standalone Part D coverage if you switch back.

The enrollment period is the same nationwide, but plan availability, premiums, and covered services vary by state and county.

What Changes During the Year?

Medicare plans are not static. Insurance carriers adjust their offerings every year, and what worked for you last year may not be the best fit now. Common changes include:

Plan premiums and out-of-pocket costs. Your monthly premium, annual deductible, and copayments for doctor visits or prescriptions can increase or decrease from one year to the next.

Covered medications. Part D plans update their formularies annually. A drug that was covered last year may move to a different tier with higher cost-sharing, or be dropped entirely.

Provider networks. Medicare Advantage plans contract with specific doctors, hospitals, and specialists. Your current doctor may leave the network, or the plan may drop a hospital you prefer.

Benefits and extras. Medicare Advantage plans often include dental, vision, hearing, or fitness benefits. These extras can be added, reduced, or eliminated year to year.

Plan availability. Some plans exit your county or ZIP code, while new plans enter the market with different structures and pricing.

What to Review During Open Enrollment

Start by comparing your current plan against what it will look like next year. Your plan is required to send you an Annual Notice of Change (ANOC) by September 30, detailing any modifications to premiums, coverage, and benefits for the upcoming year.

Review the following areas closely:

Your medications. Check whether your prescriptions remain on the plan’s formulary and at what tier. A medication moving from Tier 2 to Tier 4 can significantly increase your annual costs.

Your doctors and hospitals. Confirm that your primary care physician, specialists, and preferred hospitals are still in-network if you have a Medicare Advantage plan.

Your out-of-pocket maximum. Medicare Advantage plans cap your annual out-of-pocket spending. Compare this limit across plans, especially if you have chronic conditions or expect significant medical expenses.

Read also: Medicare Open Enrollment in the US: How to Review Your Coverage

Extra benefits. If dental, vision, or hearing coverage matters to you, verify what is included and whether the benefits justify the premium.

Total annual cost. Do not focus only on the monthly premium. Add up premiums, deductibles, copayments, and prescription costs to estimate your total spending under each plan.

The Medicare Plan Finder tool at Medicare.gov lets you enter your medications, preferred pharmacies, and doctors to compare all available plans in your area. This is the most reliable way to see personalized cost estimates (CMS, 2026).

How Coverage Decisions Affect Your Finances

As covered in foundational texts such as Principles of Finance, insurance is a financial planning tool that balances premium costs against the risk of high out-of-pocket expenses. For Medicare beneficiaries, choosing the wrong plan can mean thousands of dollars in avoidable spending if your medications become more expensive or your doctor goes out of network mid-year.

Because Medicare coverage is a significant financial decision, the Consumer Financial Protection Bureau recommends reviewing your plan annually rather than assuming your current plan remains the best value (CFPB, 2026).

Key Dates and Deadlines

Open Enrollment begins October 15 and ends December 7. Changes made during this period take effect January 1.

If you miss this window, you generally cannot change your Medicare Advantage or Part D plan until the next Open Enrollment unless you qualify for a Special Enrollment Period due to a move, loss of other coverage, or qualification for Extra Help with prescription drug costs.

There is also a separate Medicare Advantage Open Enrollment Period from January 1 through March 31, but it is more limited. During that window, you can switch from one Medicare Advantage plan to another or drop Medicare Advantage and return to Original Medicare, but you cannot join a Medicare Advantage plan for the first time or switch Part D plans if you have Original Medicare.

Common Mistakes to Avoid

Assuming your plan has not changed. Even if you are satisfied with your current plan, review the ANOC. Premiums, formularies, and networks change annually.

Ignoring new plan options. New carriers and plans enter the market each year. A plan that did not exist last year may offer better coverage or lower costs now.

Focusing only on premium. A plan with a low monthly premium but high copayments and a restrictive formulary can cost more overall than a plan with a higher premium and better coverage.

Waiting until the last minute. Plan comparison takes time, especially if you need to call the plan or your doctor’s office to verify network status. Start early.

What This Means for You

Medicare Open Enrollment is your chance to make sure your coverage fits your current health needs and budget. Review your Annual Notice of Change, compare plans using the Medicare Plan Finder, and confirm that your doctors and medications are covered before December 7.

This information is educational and general in nature. Medicare rules, plan availability, and costs vary by location and change annually. For personalized guidance on your specific situation, contact your State Health Insurance Assistance Program (SHIP) or a licensed Medicare advisor. Medicare coverage decisions are individual financial and health planning choices, not legal, medical, or personalized financial advice. Always verify current plan details, formularies, and network status with the plan directly before enrolling or making changes.