“If you’re financially able to afford a Medigap plan, I would recommend you absolutely find the policy that’s best for you that provides the coverage you need, or may need down the road,” said Kristina Raner, program manager for the Medicare Improvements for Patients and Providers Act at the National Council on Aging.

People buy Medigap policies because out-of-pocket expenses for Medicare Part A’s hospital costs and Part B’s doctor bills, outpatient care and medical equipment can be enormous. Medigap doesn’t cover Part D prescription drug costs.

Without Medigap, if you have Original Medicare, you owe a $1,600 Part A deductible in 2023 and then coinsurance of up to $400 a day if you’re in the hospital 61 to 90 days; $800 a day for 60 “lifetime reserve days.” In addition, you must pay Part B’s $164.90 monthly premium (more for high-income people), a $226 annual deductible and the gut punch: coinsurance of 20% of Medicare-approved charges.

A Medigap policy will cover some, or many, of those costs. It might even provide benefits Original Medicare doesn’t—such as dental, vision and hearing care.

You can generally use a Medigap policy wherever you go in the U.S., which makes this insurance especially useful for snowbirds who relocate to a warmer climate in winter.

Trouble is, shopping for a Medigap policy isn’t easy. “It doesn’t matter how smart you are,” says Riaz Ali, chief marketing officer at the community health organization Wider Circle.

If you want a Medigap policy, it’s best to buy one when you first enroll in Medicare and then plan to stick with it. That’s because during the six-month period when you first get Part B, you have “guaranteed access” to Medigap.

That means you can’t be rejected due to a preexisting health condition.

But if you decide to switch Medigap plans in the future, you could be turned down due to your health.

“We like to describe Medigap as like a marriage, says Raner. “You are choosing a plan and committing to it essentially forever, or as long as you’re able to pay the premium.”

Here’s how to mind the gap and get the best Medigap policy for you.

Decide which type of Medigap policy you want 

That sounds like it should be easy because they’re standardized by 10 letters: A to D, F, G and K-N (E, H, I and J aren’t sold anymore; don’t ask). Each letter signifies a different level of coverage but benefits from insurer to insurer are usually identical for the same lettered policy.

Because Medicare’s never simple, there are actually two F and G policies: regular and a high-deductible/low-premium version that kicks in once you’ve paid the annual deductible, which is $2,700 in 2023. Oh, and you can’t buy a Medigap C or F if you became eligible for Medicare on or after January 1, 2020. There are also slightly different standardized policy rules in Massachusetts, Minnesota and Wisconsin.

Exactly what each Medigap lettered policy covers would take too long to explain here, but there’s a handy guide with details on page 11 of the free online Medicare guide, “2023 Choosing a Medigap Policy.”

All Medigap plans cover Medicare Part A coinsurance and hospital costs.

Plan G is the most popular Medigap policy because it’s so comprehensive; it’s also one of the priciest ($152 a month in 2023 for a female, 65-year-old non-smoker, according to the Value Penguin personal finance site).

A Plan G policy covers the Part A deductible, coinsurance and hospital costs up to an extra 365 days after Medicare benefits are used and hospice care coinsurance or copayment; Part B coinsurance or copayments and “excess charges” (extra amounts your doctor may charge above what Medicare pays); skilled nursing facility care coinsurance and 80% of the cost of foreign travel emergency medical care.

By contrast, an A plan—the skimpiest—only covers Part A coinsurance, hospital costs and hospice care coinsurance or copayment and Part B coinsurance or copayment.

A doctor’s Medicare excess charges are covered in Plan F as well as Plan G. You can get foreign travel coverage in Plans C, D, F, G, M and N, though Medigap only pays 80% of these expenses, up to a plan’s limits.

Skilled nursing facility coverage is available in Plans C, D, F, G, M and N and partly covered by plans K and L.

Make sure you compare premiums 

The average Medigap premium is $155 a month in 2023 (or $1,860 for the year), but premiums vary wildly even for the same lettered policy.

The American Association for Medicare Supplement Insurance survey of Plan G costs for a non-smoking 65-year-old found monthly premiums in 2023 ranging from $99.30 for a woman in Dallas to $532.72 for a man in Phoenix. Annualized, that’s a range of $1,188 to $6,396.

That trade group also found that no single Medigap insurer always had the least expensive policy nor the most expensive.

How much you’ll pay for Medigap may depend on your age, health, gender, marital status, whether you smoke and where you live.

Insurers set Medigap premiums through one of three ways and you’ll want to decide which type to choose when comparing prospective policies:

1. Community-rated (or no-age-rated): With this model, your age doesn’t affect what you pay; premiums are the same for everyone in your area. They go up because of inflation or other factors. A community-rated policy can be a better buy if you first purchase it years after turning 65. It’s often the least expensive over time.

2. Issue age-rated: Here, the premium is determined by your age when you first buy the policy. You’ll pay less when you’re younger and your premium won’t rise due to your age, though it may because of inflation.

3. Attained age-rated: Its premium depends on your age when you buy the policy and rises as you get older. This type tends to be the most expensive over your lifetime, according to the Medicare Rights Center.

A Medigap policy’s premiums also tend to get higher as its smorgasbord of benefits does; Plans C, F and G offer the most types of coverage.

Two types—K and L—limit your out-of-pocket yearly costs for Medicare Part A and B. In 2023, K’s limit is $6,940 and L’s is $3,470. Beyond those thresholds, the policies pay 100% of your costs for approved services for the rest of the year.

Some insurers offer premium discounts for non-smokers or based on gender, marital status and how you’ll pay premiums. So, it’s worth asking about them.

You can also save on Medigap premiums with a Medicare SELECT policy sold in a few states. These tend to cost less than other Medigap policies because you must use hospitals and doctors in their networks for non-emergency services. Otherwise, you’ll pay some or all of what Medicare doesn’t.

If a SELECT policy sounds promising, call your state insurance department to see which companies, if any, sell it.

Find a Medigap policy covering dental, vision, or hearing

Consider looking for a Medigap policy covering one or more of the three big areas of health care Original Medicare generally doesn’t: dental, vision and hearing. Such Medigap coverage is pretty rare, though.

A 2021 Commonwealth Fund study Ali co-wrote found that just 7% of Medigap plans provided access to these additional benefits, down from 12% in 2016. When dental, vision or hearing coverage is available in Medigap, that tends to be in Plan G.

“Are those benefits any more common than they were in 2021? I would say they’re about the same,” says Ali. The only way to find out if a Medigap policy offers this additional coverage is to ask the company or an agent selling it.

Get help picking the right Medigap policy

You can do this through the Medicare site’s Plan Finder, by speaking to an unbiased expert at your State Health Insurance Assistance Program (SHIP), working with a Medigap agent or broker and by calling Medigap insurance companies.

At the Medicare Plan Finder, after you type in your ZIP code, age, sex and whether you use tobacco, the tool shows you all the Medigap policies you could buy, Plan Letter by Plan Letter.

You’ll learn the plan’s monthly premium range; how much of copays and coinsurance it will pay, whether it will pick up your Part A and B deductibles and other coverage details.

Once you choose a particular Medigap lettered policy, you’ll then see all the companies that sell it where you live, which pricing method each insurer uses, what you’d pay and how to contact the company.

A SHIP counselor can guide you through the types of Medigap policies sold in your state and how to choose among the letter plans. This pro won’t recommend a particular company or policy, though.

“The SHIP programs are really good resources to get yourself oriented,” says Ali.

A Medigap agent or broker, who gets paid by insurers, can do the legwork for you and suggest prospective policies based on your preferences.

But watch out for possible conflicts of interest. A scathing 2023 report by Sen. Elizabeth Warren, “Sales Before Seniors,” found that many Medigap companies “offer luxurious vacations and cash bonuses to agents and brokers, creating incentives for them to steer seniors to Medigap products that may not be the best fit for their financial and health needs.”

Before hiring an agent, says American Association for Medicare Supplement Insurance Director Jesse Slome, ask how many insurers they work for and which ones. You’ll want to hear the agent represents at least several—including big names like Aetna, Cigna, Humana, Mutual of Omaha and UnitedHealthcare—to avoid getting steered due to the company’s sales incentives.

Ask an agent or Medigap insurer for the company’s history of rate increases, too, since you’ll likely be keeping the policy for the long run and will want to avoid frequent premium hikes.