Medicare Advantage vs. Medigap in Idaho: How to Choose

Short answer: Medicare Advantage replaces how you receive Original Medicare with a private plan that usually includes drug coverage, uses a provider network and charges copays up to a yearly limit. Medigap keeps Original Medicare, pays some or all of its gaps, works with any provider that accepts Medicare, and needs a separate Part D plan. In Idaho, Medigap holders also get a yearly 63-day birthday window to switch policies without health questions.

Two Different Structures, Not Two Grades

Medicare Advantage (Part C) is offered by private insurers approved by Medicare. You still have Medicare and still pay your Part B premium, but the plan handles your hospital and medical benefits. Most plans include Part D drug coverage, and many add extras such as dental, vision or hearing benefits. You use the plan’s network, may need referrals, and pay copays or coinsurance as you go. Every plan has a yearly out-of-pocket limit for covered in-network care; CMS sets a ceiling on that limit each year.

Medigap (Medicare Supplement Insurance) is extra insurance from a private company that helps pay your share of Original Medicare costs, such as deductibles, coinsurance and copayments. Plans are standardized by letter, so Plan G from one company covers the same benefits as Plan G from another; only price and service differ. Medigap has no network: if a provider accepts Medicare, your Medigap pays its share. You add a separate Part D plan for prescriptions.

Medicare Advantage vs. Medigap, Side by Side

How the two paths compare (sources: Medicare.gov; CMS)
Feature	Medicare Advantage	Original Medicare + Medigap
Doctors and hospitals	Plan network; rules vary by plan type (HMO, PPO)	Any provider in the U.S. that accepts Medicare
Drug coverage	Usually built in	Separate Part D plan
Monthly premium	Often low, plus your Part B premium	Higher, plus Part B and Part D premiums
Cost when you use care	Copays and coinsurance up to a yearly limit	Little or nothing, depending on the plan letter
Extras (dental, vision, hearing)	Often included in some form	Not included; buy separately if needed
Prior authorization	Can apply to some services	Follows Original Medicare rules
Travel	Mostly local network; check the plan	Works with Medicare providers nationwide

A useful way to think about it: Advantage is variable cost, Medigap is fixed cost. A healthy year usually costs less on Advantage. A heavy year, with surgery or ongoing treatment, can cost more, up to the plan’s limit. With Medigap, the premium is the main cost every year. People who choose high-deductible Plan G pay a lower premium in exchange for a deductible of $2,950 in 2026 and $3,050 in 2027.

Extras matter to some people. If dental and vision are what tip you toward Advantage, compare what the plan actually pays with a standalone policy; our dental, vision and hearing page explains those options.

Idaho’s Medigap Birthday Rule

In most states, once your 6-month Medigap open enrollment period ends, a Medigap insurer can use medical underwriting. That can leave people stuck with a policy whose price keeps climbing. Idaho changed that.

Following Senate Bill 1143, signed in April 2021, the Idaho Department of Insurance adopted rules under which, after February 28, 2022, Medigap policyholders may change plans annually on a guaranteed-issue basis during a 63-day enrollment period beginning on their birthday. In practice, per the Department’s guidance:

You can move to a policy with the same or fewer benefits, from any company offering Medigap in Idaho. If you have Plan G, you can buy Plan G or a plan with fewer benefits; you cannot upgrade.
It applies only to people who already have a Medigap policy. It does not apply to Medicare Advantage enrollees or to employer group Medigap plans.
Your Part B deductible does not restart when you switch. On a high-deductible plan, the plan deductible may restart with a new policy, so ask before you switch.
Make sure the new policy is issued before you cancel the old one.

Because Plan G is Plan G at every company, the birthday rule effectively lets Idahoans re-shop the price of the same coverage every year. We check it for our Medigap clients each birthday. The Medigap cost comparison calculator helps compare plan letters.

Community Rating in Idaho

The same rule change ended issue-age rating for new Idaho Medigap policies issued after February 28, 2022. The Department describes the new approach as community rating: one rate for all ages in the group, rather than a price that depends on the age you were when you bought. Existing issue-age policies continue, and companies cannot force anyone to move. People who have Medicare because of a disability can be charged up to 150% of the premium for people eligible because of age.

The Switching Rule That Matters Most

You can leave Medicare Advantage and return to Original Medicare during Open Enrollment (October 15 to December 7) or the Medicare Advantage Open Enrollment Period (January 1 to March 31). That part is easy. Getting a Medigap policy afterwards is not guaranteed. Outside your initial Medigap open enrollment or another guaranteed-issue right, an insurer may ask health questions and can decline you, and the Idaho birthday rule does not help because you would not yet have a Medigap policy.

That makes the choice at 65 more consequential than it looks. If you might want Medigap later, your first 6 months on Part B are the safest time to get it. Our enrollment periods guide has every window in one table.

How to Decide

Start with three questions:

Who are your doctors and which hospital system do you use? In the Treasure Valley, networks differ between plans. Check every provider; our guide on checking doctors and drugs shows how.
How much care do you expect, and how would you handle a heavy year? Compare the Advantage plan’s yearly limit with the Medigap premium you would pay regardless.
Do you travel or split the year out of state? Medigap travels with Original Medicare; many Advantage networks are local.

For a longer, scenario-based comparison, see our blog post Medicare Advantage vs. Medicare Supplement in Idaho, and our Plan G vs. Plan N post if you are leaning toward Medigap.

Weighing Advantage against Medigap?

We will lay out both paths with your doctors, hospitals and prescriptions, using plans we represent in your Idaho county, and show the yearly cost of each.

Request a free comparison Call 208-350-9933

Frequently Asked Questions

What is the Idaho Medigap birthday rule?

Since March 2022, Idaho lets people who already have a Medigap policy change plans each year on a guaranteed-issue basis during a 63-day window that begins on their birthday. The new policy must have the same or fewer benefits, and it can come from any company selling Medigap in Idaho. It does not apply to Medicare Advantage or to employer group Medigap plans.

Can I switch from Medicare Advantage back to Medigap in Idaho?

You can return to Original Medicare during Open Enrollment or the Medicare Advantage Open Enrollment Period, but buying a Medigap policy afterwards is a separate step. Unless you have a guaranteed-issue right, an insurer may ask health questions and can decline you. Idaho’s birthday rule only helps people who already hold a Medigap policy.

Does Medigap include prescription drug coverage?

No. Medigap policies sold today do not include drug coverage, so people with Original Medicare and Medigap usually add a standalone Part D plan. Most Medicare Advantage plans include drug coverage in the same plan.

Are Medigap premiums in Idaho based on my age?

For Medigap policies issued in Idaho after February 28, 2022, issue-age rating is not permitted; the Idaho Department of Insurance describes the new policies as community rated. Older issue-age-rated policies stay in force, and nobody is forced to move. People eligible for Medicare because of a disability can be charged up to 150% of the age-based premium.

Which one is cheaper, Medicare Advantage or Medigap?

It depends on how much care you use. Medicare Advantage often has a lower monthly premium but charges copays and coinsurance as you use care, up to the plan’s yearly limit. Medigap has a higher premium but leaves little to pay at the point of care. Comparing your likely total yearly cost, not just the premium, is the fair test.

Coverage pages for this topic: Medicare Advantage · Medicare Supplement · Medicare Part D. Other topics in the Learning Center: Health Insurance (ACA), Life Insurance, Final Expense, Annuities, Long-Term Care, Disability Insurance, Supplemental Health, Short-Term Medical, Travel Insurance.

Sources

Figures are labelled with the year they apply to and were checked against the official sources above on the review date. Rules and amounts change; confirm current figures with the agency that publishes them. This guide is general education, not individual advice.