Medicare 2026

Medicare Advantage vs. Medigap: Which Path Fits You?

CHANDLER, Ariz. — Turning 65 in the East Valley comes with a choice that shapes the rest of your Medicare life: stay on Original Medicare and add a Medigap policy, or move your coverage into a Medicare Advantage plan. Both are legal, both are common, and both are approved ways to get your Medicare benefits. But they are built very differently — and the differences matter long after you sign up.

Key takeaways

• Original Medicare with a Medigap policy and Medicare Advantage are two separate structures — you pick one path at a time, not both.
• Medigap helps pay the out-of-pocket costs Original Medicare leaves behind, while Medicare Advantage replaces how you receive your Part A and Part B benefits.
• Two Part D figures to know: the out-of-pocket drug cost cap is $2,100 in 2026 and $2,400 in 2027, and the Part D deductible cannot exceed $615 in 2026 or $700 in 2027, no matter which path you choose.
• The Annual Enrollment Period runs Oct. 15 – Dec. 7, and Medicare Advantage members get a second window Jan. 1 – March 31 to switch or return to Original Medicare.

The two paths, side by side

Path 1: Original Medicare + Medigap (+ usually a separate Part D drug plan). Original Medicare is the federal program — Part A (hospital) and Part B (doctor and outpatient). It pays a large share of your covered care, but not all of it. A Medigap policy (also called Medicare Supplement Insurance) is sold by private insurers and helps cover what Original Medicare doesn't — things like coinsurance and hospital deductibles. Because Original Medicare does not include drug coverage, most people on this path also enroll in a stand-alone Part D plan.

Path 2: Medicare Advantage (Part C). Medicare Advantage is offered by private insurers approved by Medicare. When you enroll, that plan becomes the way you get your Part A and Part B benefits — and, in most cases, your Part D drug coverage too. Advantage plans often use networks (HMO or PPO) and require you to follow plan rules for referrals, prior authorization, and in-network care.

You cannot use a Medigap policy with a Medicare Advantage plan. That's the single biggest structural difference to understand.

How the money flows

On the Medigap path, Original Medicare pays first, and your Medigap policy pays its share of what's left. Your costs are more predictable month to month because the supplement smooths out the bills. You'll typically pay a Medigap premium plus your Part B premium and a Part D premium.

On the Medicare Advantage path, the plan sets its own copays, coinsurance, and an annual out-of-pocket maximum for medical services. You still owe your Part B premium, and you may or may not owe a separate plan premium. Costs can be lower in a healthy year and climb toward that out-of-pocket max in a heavy-use year.

For prescriptions, the rules are the same either way: the Part D deductible cannot exceed $615 in 2026 and $700 in 2027, and once you hit the annual out-of-pocket cap on covered Part D drugs — $2,100 in 2026 and $2,400 in 2027 — you pay nothing more for covered Part D drugs the rest of the year. The old "donut hole" coverage gap was eliminated in 2025, so Part D now moves through three phases instead of four. If your drug costs are lumpy, the Medicare Prescription Payment Plan lets you spread them across the calendar year.

Doctors, networks, and travel

This is where Chandler residents often get tripped up. Original Medicare is accepted by any provider in the country that takes Medicare, which is most of them. A Medigap policy travels with you — helpful if you spend part of the year outside Arizona or split time with family in another state.

Medicare Advantage plans are built around local networks. Chandler is in Maricopa County, where 79 Medicare Advantage plans from 16 carriers are offered for 2027 (down from 88 plans in 2026), but each plan has its own contracted hospitals, specialists, and pharmacies. If you see a snowbird pattern in your life, or you're loyal to a specific doctor or health system, check the network before you enroll.

Medical underwriting: the timing trap

Here's the mistake that quietly costs people the most: when you first become eligible for Medicare, you have a one-time Medigap Open Enrollment Period — six months starting when you're 65 or older and enrolled in Part B. During that window, insurers must sell you a Medigap policy at their best available rate, regardless of health history.

After that window closes, in most states, insurers can use medical underwriting. That means if you start on Medicare Advantage and later try to switch to Original Medicare with a Medigap policy, you may be turned down or charged more based on your health. Arizona follows the federal baseline on this. It doesn't mean Advantage is wrong for you — it means the choice deserves a careful look up front.

Key dates to remember

• Initial Enrollment Period: the seven-month window around your 65th birthday.
• Annual Enrollment Period: Oct. 15 – Dec. 7 each year to join, switch, or drop a Medicare Advantage or Part D plan.
• Medicare Advantage Open Enrollment: Jan. 1 – March 31 to switch Advantage plans or return to Original Medicare.
• IRMAA thresholds for 2026: higher-income surcharges on Part B and Part D begin above $109,000 in income for a single filer.