Medicare 2026

Original Medicare + Medigap vs. Advantage: A Missoula Guide

# Original Medicare with a Medigap plan vs. Medicare Advantage: how to think it through

MISSOULA, Mont. — If you're turning 65 in the Garden City, or helping a parent sort through mail from insurance companies, you've probably run into the same fork in the road: should you stick with Original Medicare and add a Medigap policy, or go with a Medicare Advantage plan?

Both are legitimate ways to get your Medicare coverage. But they're built differently. Understanding the structure — how the pieces fit together — makes the rest of the decision much easier.

The two paths, in plain English

Path 1: Original Medicare + Medigap (and usually a Part D drug plan). Original Medicare is the federal program run by CMS. It has two parts: Part A (hospital) and Part B (doctor and outpatient). You can see any doctor or hospital in the country that accepts Medicare — and most do. Original Medicare pays its share, and you're responsible for the rest.

That "rest" is where Medigap comes in. A Medigap policy (also called Medicare Supplement Insurance) is sold by a private insurance company and helps pay some of the out-of-pocket costs Original Medicare leaves behind, like coinsurance and deductibles. Because Original Medicare doesn't include prescription drug coverage, most people on this path also add a stand-alone Part D drug plan.

Path 2: Medicare Advantage (Part C). Medicare Advantage is offered by private insurance companies approved by Medicare. When you enroll in an Advantage plan, you're still in Medicare, but the plan takes over administering your Part A and Part B benefits, and usually bundles in Part D drug coverage too. Many plans also include extras like routine dental, vision, or hearing.

Advantage plans typically use provider networks (HMO or PPO) and often require referrals or prior authorization for certain services. Instead of a Medigap policy filling in the gaps, the plan itself sets your copays, coinsurance, and a yearly out-of-pocket maximum.

The structural difference that matters most

Here's the cleanest way to think about it:

• Original Medicare + Medigap spreads your costs out. You pay monthly premiums (Part B, Medigap, and Part D), and in exchange your surprise bills stay small. Access is wide open — any Medicare provider, no network.
• Medicare Advantage concentrates costs at the point of care. Premiums are often lower, but you pay copays as you use services, up to the plan's annual out-of-pocket cap. Access is defined by the plan's network and rules.

Neither approach is universally better. It depends on your budget, your health, how often you travel, and whether you'd rather pay more up front for predictability or less up front with more variability later.

What's happening in Missoula County

Missoula is in Missoula County, and that's the geography Medicare uses to determine which plans are offered where you live. Both Medicare Advantage plans and stand-alone Part D plans are available to county residents, and the specific lineup can change from year to year. Medigap policies, on the other hand, are regulated at the state level in Montana and are sold by private insurers licensed there.

To see the current plan options for your ZIP code, the Medicare Plan Finder at medicare.gov/plan-compare is the official tool. It pulls directly from CMS data.

2026 numbers worth knowing

A few program-level figures apply no matter which path you choose:

• Part D out-of-pocket cap: $2,100 in 2026. Once your drug spending hits that limit, you pay $0 for covered Part D drugs the rest of the year.
• Part D maximum deductible: $615 in 2026 (plans can set a lower deductible, but not higher).
• The coverage gap ("donut hole") is gone as of 2025. Part D now has three phases: deductible, initial coverage, and catastrophic.
• Medicare Prescription Payment Plan: an optional program that lets you spread your yearly drug costs into monthly payments instead of paying all at once at the pharmacy.
• IRMAA (the income-related surcharge on Part B and Part D) starts above $109,000 in income for a single filer in 2026.

These rules apply whether your drug coverage comes through a stand-alone Part D plan or is built into a Medicare Advantage plan.

Enrollment windows to circle on the calendar

• Medigap Open Enrollment: a one-time, six-month window that starts the month you're 65 and enrolled in Part B. During this window, insurers can't turn you down or charge you more for health reasons. Outside of it, Montana rules on medical underwriting apply.
• Annual Enrollment Period (AEP): October 15 – December 7 each year. This is when you can join, switch, or drop a Medicare Advantage or Part D plan for the following year.
• Medicare Advantage Open Enrollment: January 1 – March 31. If you're already in an Advantage plan, you get one chance during this window to switch to a different Advantage plan or return to Original Medicare (and pick up a Part D plan).

Questions Missoula readers often ask

Can I have both a Medicare Advantage plan and a Medigap policy? No. It's actually against federal law for an insurance agent to sell you a Medigap policy if you're enrolled in a Medicare Advantage plan. Medigap only works with Original Medicare.

If I choose Medicare Advantage now, can I switch back to Original Medicare later? Yes, during the right enrollment window. But be aware: outside your initial Medigap open enrollment, insurance companies in Montana may be able to use medical underwriting when you apply for a Medigap policy — meaning your health history can affect whether you're accepted or what you pay. This is worth understanding before you make an initial choice.

Does Original Medicare cover me when I travel outside Montana? Yes. Original Medicare works with any provider nationwide that accepts Medicare. Medicare Advantage plans, because they use networks, may cover out-of-area care differently — usually emergencies are covered anywhere, but routine care may not be. Check the plan's rules if you spend part of the year elsewhere.

Where can I get help sorting this out without a sales pitch? Montana's State Health Insurance Assistance Program (SHIP) offers free, unbiased counseling to Medicare beneficiaries. It's a good first call.

Where to go next

• Medicare.gov — official plan comparisons, coverage rules, and enrollment: medicare.gov
• 1-800-MEDICARE (1-800-633-4227) — 24/7 help from Medicare directly
• Montana SHIP — free local counseling for Medicare questions: dphhs.mt.gov/sltc/aging/SHIP or 1-800-551-3191

Take your time. The choice between Original Medicare with a Medigap plan and Medicare Advantage isn't about which one is "better" — it's about which structure fits your life. Ask questions, use the official tools, and don't be afraid to lean on a SHIP counselor before signing anything.