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Medicare Open Enrollment: Everything You Need to Know

When it starts and ends, how to choose a Part D or Medicare Advantage plan and why it’s important to compare your options this year


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Key takeaways

Every October, Medicare gives its more than 67 million beneficiaries a chance to review coverage and make changes for the coming year.

While experts say too many enrollees overlook this opportunity, evaluating your options this year is especially important because of big changes coming to Medicare in 2025.

If you’re happy with your current Medicare Part D prescription plan or Medicare Advantage plan, you can leave your coverage as is. But costs and coverage for this private insurance can change significantly from year to year, and companies may enter or leave the business.

Comparing your options is always a good idea, especially if your health has changed.

“Most people don’t pay much attention to the open enrollment period, and that can come at a cost,” says Tricia Neuman, KFF senior vice president and executive director of the nonpartisan nonprofit’s Program on Medicare Policy. Beneficiaries can save hundreds or even thousands of dollars by finding a prescription drug or Medicare Advantage plan that better meets their needs.

When is Medicare open enrollment?

Medicare open enrollment runs Oct. 15 to Dec. 7 each year. The changes you select take effect Jan. 1.

This year’s open enrollment is particularly important. For the first time, enrollees with Part D or Medicare Advantage plans will have a $2,000 annual out-of-pocket spending cap on covered prescriptions.

But this limit could prompt insurers to make other changes to their costs and coverage, so investigate your options carefully. If you miss open enrollment, you may not have another chance until next year to switch, except in limited circumstances.

What changes can I make during open enrollment?

If you have original Medicare:

  • You can sign up for a Part D prescription plan or switch from one Part D plan to another.
  • You can leave original Medicare and choose a private Medicare Advantage plan.

If you have Medicare Advantage:

  • You can switch from one Medicare Advantage plan to another.
  • You can leave Medicare Advantage for original Medicare and choose a Part D prescription plan.

You can get a second chance to make changes during Medicare Advantage’s special open enrollment period Jan. 1 through March 31. That includes switching from one Medicare Advantage plan to another or returning to original Medicare and getting a stand-alone Part D prescription plan.

How do I prepare for open enrollment decisions?

If you have original Medicare, most people buy a separate Part D plan to cover prescription drugs. A review of your Part D options every year is important to make sure you have the best plan for the next year.

First, review your annual notice of change. If you have Part D, your plan must send you a notice by the end of September outlining revisions to your costs and coverage. Make sure your prescriptions remain covered and find out if your premiums and other out-of-pocket costs will rise.

Next, review all Part D options in your area. Use the Medicare Plan Finder to compare them.

  • Confirm the plan includes all your medications. They can change their list of covered drugs, called a formulary, from year to year. If your drugs aren’t listed, they won’t be subject to the $2,000 spending cap.
  • Learn what you could pay in total — premiums plus out-of-pocket costs — for your medications. A plan with low premiums may have higher total expenses if copayments, the fixed amount you spend for a prescription after you’ve met your deductible, are high.
  • Make sure your preferred pharmacies are included.
  • Find out if your drugs have coverage requirements such as prior authorization and step therapy.

If you have Medicare Advantage, this private insurance alternative to original Medicare, also known as Part C, bundles Parts A, B and usually D.  

First, read your letter. Medicare Advantage plans send members an annual notice of change by the end of September each year. It explains revisions in benefits, costs, covered drugs and provider networks that take effect Jan. 1.

Next, compare Medicare Advantage plans in your area using the Medicare Plan Finder. Learn details such as:  

  • Premiums and out-of-pocket costs for your typical medical care.
  • Covered drugs and how much you’ll pay for them.
  • Doctors, facilities and other providers. Check the plan’s website or ask your doctors if they participate.
  • Extra charges for out-of-network providers or facilities. Some plans impose higher copayments if you don’t use participants on their list. Others don’t cover out-of-network providers except for emergencies.
  • A plan’s out-of-pocket maximum. MA plans are required to limit your Part A and Part B expenses, different from the $2,000 ceiling for prescription drugs. In 2024, the limit must be $8,850 or less for in-network services or $13,300 for the covered total of in-network and out-of-network services. Some have lower limits.
  • Potential special provisions for chronic conditions.
  • The plan’s star ratings, which grade using several quality measures.
  • If the plan offers other coverage, such as dental, hearing and vision care.

Video: Original Medicare vs. Medicare Advantage, What's the Difference?

Why switch between original Medicare, Medicare Advantage?

Original Medicare to Medicare Advantage. Medicare Advantage all-in-one plans for health care and prescriptions may intrigue you, but make sure your providers participate. Otherwise, you may pay more or have no coverage outside the network.

You’ll likely have to jump through additional hoops to get some of the care you want: Medicare Advantage plans may require more prior authorization than original Medicare before covering some services, and you may need a referral from your doctor to see specialists.

Medicare Advantage to original Medicare. If you switch back to original Medicare, you can use any participating provider and choose a stand-alone Part D plan.

You’ll need to pay a separate premium for Part D. And if you’re eligible, you can buy a Medicare supplement policy, or Medigap, to help with Medicare deductibles and copayments, also for a separate premium.

Medigap isn’t part of annual open enrollment. A policy can be bought at any time of the year.

However, Medigap insurers in most states can reject you or charge more because of preexisting conditions if more than six months have passed since you signed up for Medicare Part B — unless you qualify for a guaranteed issue period, such as changing your mind within 12 months of choosing Medicare Advantage for the first time or moving out of your plan’s service area.  

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Get help choosing a Medicare plan

The following resources can help when making open enrollment decisions.

State Health Insurance Assistance Programs (SHIPs) are available in each state for one-on-one assistance from trained counselors and group seminars during open enrollment season. They can educate you about state-specific rules and help you figure out whether you are eligible for financial help with premiums and out-of-pocket costs.

Medicare’s Plan Finder compares all Part D and Medicare Advantage plans in your area. You also can call 800-MEDICARE (800-633-4227) or use its live chat tool 24 hours a day seven days a week, except for some federal holidays.

This story, originally published Sept. 22, 2022, was updated with information about the 2025 open enrollment season.

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