Medicare 2026

How Original Medicare and Medicare Advantage differ in Phoenix

PHOENIX — Choosing how to receive your Medicare benefits is one of the biggest decisions you'll make as you approach 65, and in Phoenix it usually comes down to two very different paths. You can stay with Original Medicare and add a Medigap policy, or you can move your coverage into a Medicare Advantage plan. Both are legitimate, both are regulated by the Centers for Medicare & Medicaid Services (CMS), and both work in very different ways.

Understanding the structure of each path — not the marketing around them — is the surest way to avoid a costly mistake later.

Key takeaways

• Original Medicare plus a Medigap policy and Medicare Advantage are two separate ways to get your Medicare benefits, and you generally can't use both at the same time.
• Medigap helps pay the out-of-pocket costs left behind by Original Medicare, while Medicare Advantage replaces how you receive Parts A and B through a private plan.
• Your best window to buy a Medigap policy with guaranteed acceptance is the 6-month Medigap Open Enrollment Period that starts when you're 65 and enrolled in Part B.
• The Annual Enrollment Period runs Oct. 15 – Dec. 7, and Medicare Advantage Open Enrollment runs Jan. 1 – March 31 each year.

Path one: Original Medicare plus Medigap

Original Medicare is the federal program itself — Part A (hospital) and Part B (doctor and outpatient). You can see any provider in the country who accepts Medicare, and there's no network. But Original Medicare doesn't cap what you pay out of pocket each year, which is where Medigap comes in.

Medigap, also called Medicare Supplement Insurance, is a separate policy you buy from a private insurer. It helps pay the deductibles, coinsurance and copayments that Original Medicare leaves behind. Medigap policies are standardized, so a Plan G from one company covers the same core things as a Plan G from another company.

With this path, prescription drug coverage isn't automatic. You add it by enrolling in a stand-alone Part D drug plan.

Path two: Medicare Advantage (Part C)

Medicare Advantage — also known as Part C — is offered by private insurers approved by Medicare. When you enroll, the plan takes over the job of delivering your Part A and Part B benefits, and most Advantage plans also include Part D drug coverage in one package.

Advantage plans use networks — usually HMO or PPO structures — and often include extras that Original Medicare doesn't cover, like routine dental, vision or fitness benefits. In exchange, you generally agree to use the plan's network of doctors and hospitals and follow its rules, such as prior authorization for certain services.

Phoenix is in Maricopa County, where a large number of Medicare Advantage plans are available from multiple carriers. The Medicare Plan Finder at medicare.gov lets you see the current list for your ZIP code.

The structural difference in one sentence

Medigap works with Original Medicare to fill in its gaps; Medicare Advantage replaces how you receive your Original Medicare benefits by routing them through a private plan.

That single distinction drives almost every other difference — networks, referrals, drug coverage, travel coverage, and how appeals work.

Timing matters more than most people realize

The path you pick at 65 isn't always easy to change later. Here's why:

• Medigap Open Enrollment. You get one 6-month window that starts the month you're 65 and enrolled in Part B. During that window, insurers must sell you a Medigap policy at their best rate regardless of your health. After that window closes, in most states insurers can use medical underwriting — meaning they can charge you more or turn you down based on your health history.
• Switching from Advantage to Medigap later. If you start in Medicare Advantage and want to switch to Original Medicare plus Medigap years down the road, you may face underwriting for the Medigap policy. Arizona does not have a broad "birthday rule" or similar guaranteed-issue protection outside federal rules, so this is worth thinking through before you enroll.
• Annual windows to change. The Annual Enrollment Period (Oct. 15 – Dec. 7) lets you change Advantage or Part D plans for the following year. The Medicare Advantage Open Enrollment Period (Jan. 1 – March 31) lets people already in an Advantage plan switch to a different Advantage plan or return to Original Medicare.

2027 program-level costs worth knowing

Regardless of which path you choose, some Medicare figures are set at the federal level. Here are the confirmed 2027 Part D numbers:

• Part D out-of-pocket cap: $2,100 in 2026 and $2,400 in 2027. Once your drug spending hits that amount, you pay nothing for covered drugs the rest of the year.
• Part D maximum deductible: $615 in 2026 and $700 in 2027.
• The old coverage gap, or "donut hole," is eliminated as of 2025. Part D now has three phases.
• The Medicare Prescription Payment Plan lets you spread your yearly drug costs into monthly bills instead of paying at the pharmacy counter.
• IRMAA — the income-related surcharge on Part B and Part D premiums — starts above $109,000 in income for a single filer in 2026.

How to decide without guessing

There is no universal "right" answer between these two paths. The right one depends on your doctors, your prescriptions, whether you travel or live part of the year outside Arizona, your budget, and how much predictability you want in your health spending.

Two free, unbiased resources can help:

• Medicare.gov — use the Plan Finder tool and read the official "Medicare & You" handbook.
• 1-800-MEDICARE (1-800-633-4227), available 24/7.
• Arizona SHIP — the State Health Insurance Assistance Program offers free, one-on-one counseling from trained volunteers who don't sell insurance. You can reach Arizona SHIP through the Arizona Department of Economic Security or by calling 1-800-432-4040.