Medicare Supplement

How Medigap letter plans work for Mesa Medicare enrollees

MESA, Ariz. — If you've spent any time comparing Medicare options, you've probably run into a wall of letters: Plan A, Plan G, Plan N, and more. Those letters refer to Medicare Supplement Insurance, better known as Medigap. It's one of the most misunderstood corners of Medicare — and getting it wrong can leave you paying for coverage you don't need, or missing coverage you do.

Here's a plain-English guide to what Medigap does, how the standardized letter plans work, and where Mesa residents can get unbiased help.

What Medigap actually is

Medigap is private insurance that works alongside Original Medicare (Part A and Part B). It doesn't replace Medicare — it fills in some of the gaps Medicare leaves behind, like coinsurance, copayments, and deductibles.

So if you go to the hospital and Medicare pays its share, your Medigap policy can pick up part or all of what's left. You pay a monthly premium to the private insurance company for that protection, on top of your regular Part B premium.

Important: Medigap only works with Original Medicare. If you're enrolled in a Medicare Advantage plan (Part C), you cannot also use a Medigap policy. It's one path or the other.

Why the plans are labeled with letters

Here's the part that trips people up. Medigap plans are standardized by the federal government. That means Plan G from one company covers exactly the same things as Plan G from another company. The benefits inside each lettered plan are set by law.

What can differ between companies:

• The monthly premium
• Customer service and billing
• Extra perks some carriers add (like gym memberships or dental discounts)

So when you're comparing, you're really comparing price and company reputation — not the core benefits — as long as you're looking at the same letter.

The currently sold plans in most states are A, B, D, G, K, L, M, and N. Plans C and F are only available to people who became eligible for Medicare before January 1, 2020. Massachusetts, Minnesota, and Wisconsin have their own standardized systems.

What Medigap does NOT cover

This is where readers often get surprised. Medigap does not cover:

• Prescription drugs. For that, you need a separate Part D plan.
• Dental, vision, or hearing care in most cases.
• Long-term care (like a nursing home stay beyond what Medicare briefly covers).
• Private-duty nursing.

If you want drug coverage — and most people should have some form of it to avoid a lifelong late-enrollment penalty — you'll need to add a standalone Part D plan.

The enrollment window most people miss

Here's the mistake that costs Mesa retirees the most money: waiting too long to buy a Medigap policy.

You get a six-month Medigap Open Enrollment Period that starts the month you're 65 or older AND enrolled in Part B. During that window, insurance companies must sell you any Medigap policy they offer at the best available rate — no matter your health history.

Once that window closes, in most states insurers can use medical underwriting. That means they can charge you more, or deny you coverage entirely, based on preexisting conditions. Arizona follows the federal baseline, so Mesa residents should treat that six-month window seriously.

How Medigap fits with 2026 Medicare changes

Even with Medigap, you still deal with Part D separately for drugs. A few 2026 numbers worth knowing:

• Part D now has a $2,100 annual out-of-pocket cap on covered drugs.
• The Part D deductible can be no higher than $615.
• The old "donut hole" coverage gap is gone — Part D now has three simpler phases.
• The Medicare Prescription Payment Plan lets you spread drug costs across the year in monthly payments.
• Higher-income beneficiaries may pay IRMAA surcharges, which kick in above $109,000 for a single filer in 2026.

Medigap premiums themselves are set by each insurance company and can change year to year.

Availability around Mesa

Mesa is in Maricopa County, where a wide range of Medigap carriers do business. Because Medigap plans are standardized, the shopping question isn't "which plan has better benefits" — it's "which company offers the letter I want at a fair price, with service I trust." Rates for the same lettered plan can vary quite a bit between insurers.