Millions of retirees are in the thick of Medicare open enrollment, which runs from Oct. 15 to Dec. 7, but many find the process challenging. Some don’t understand the difference between Original Medicare and Medicare Advantage, many are overwhelmed by Medicare advertising, and only 4 in 10 people review their plan options each year, according to a July 2022 report from health care consulting firm Sage Growth Partners.

This leads to Medicare open enrollment misses, including not confirming that your providers are in-network for the next plan year and not comparing your Medicare Part D prescription drug coverage with other available options.

Medicare Guide 2023: More guides and advice for Medicare beneficiaries

Here are some common Medicare open enrollment mistakes:

1. NOT CHECKING YOUR DOCTORS FOR 2023

If you have a Medicare Advantage plan, you generally must get medical care from doctors within that plan’s network — and a plan’s network can change a t any time. Before you decide to stick with the plan you’re in, make sure your preferred medical providers are still in the plan’s network in 2023.

This may require some legwork on your part, since websites and provider directories aren’t always up to date.

“I was just at a client, and (the plan) said their doctor wasn’t in-network, and it took us calling the provider and looking up a different site on the network side,” says Evan Tunis , president of Florida Healthcare Insurance. “The best thing I would advise is to call the doctor’s office and just confirm with them.”

2. NOT COMPARING PRESCRIPTION DRUG PLANS

Whether you have Original Medicare or Medicare Advantage, your prescription drug coverage comes from a private insurance company, and it may change what it covers each year. Your regular prescription medication may cost more in 2023, or an insurer may not cover it at all. (Another plan may also cover it for less.)

It pays to plug your drugs into Medicare.gov to see what plans they suggest for you. Pro tip: If you log into your account at Medicare.gov, your medication history is already there.

“It makes it much easier for them to shop for the next year,” says Katy Votava, who holds a doctorate in health economics and nursing and is president and founder of Goodcare, a consulting firm focused on the economics of Medicare. “They don’t have to tediously put everything in line by line and milligram by milligram.”

3. THINKING ALL DOCTORS WILL TAKE YOUR PPO PLAN

A preferred provider organization, or PPO, plan, is a health plan that allows members to see out-of-network doctors, usually for a higher price. People sometimes think that because they have a Medicare Advantage PPO, they’ll be able to see any doctor they want. But providers don’t always take out-of-network coverage.

“Providers … can just refuse someone at the point of service if they don’t want to bill the plan,” Tunis says.

Case in point: Mayo Clinic in Florida is out-of-network with most Medicare Advantage plans and won’t schedule appointments for members with out-of-network Medicare Advantage coverage.

For full provider choice, choosing Original Medicare with Medicare Supplement Insurance, or Medigap, “is the most prudent solution,” Tunis says.

4. BEING SWAYED BY THE SPLASHY ADS

Medicare open enrollment season means Medicare commercials galore, and Medicare Advantage plans have appealing things to offer like no premiums and some coverage for hearing, dental and vision care.

But shopping for your health coverage is about more than the side benefits. “Most of the time, honestly … they don’t cover that much dental,” Votava says. “Hearing aid coverage is also very limited, and that’s not the reason to change your plan, so be very careful.”

More important, Votava says, is making sure the plan covers your doctors and prescriptions for the next year.

5. WAITING TOO LONG TO ASK FOR HELP

Medicare open enrollment ends Dec. 7, but you don’t want to wait until the last day — or even the last week — to start your research. If you have questions, you can get help through programs like the State Health Insurance Assistance Program, or SHIP. Counselors at SHIP programs can offer free assistance with your Medicare choices, but they get busy.

SHIP programs in some parts of the country are booking several weeks out. “If you need help, don’t wait,” Votava says.

You can find your local SHIP at shiphelp.org.

This article was provided to The Associated Press by the personal finance site NerdWallet. Kate Ashford is a writer at NerdWallet. Email: kashford@nerdwallet.com. Twitter: @kateashford.