Key Takeaways
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Once you enroll in a Medicare Advantage plan, switching to a Medicare Supplement (Medigap) later can be difficult, especially if you’re outside your one-time guaranteed issue period.
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Medicare Advantage plans often come with networks, prior authorizations, and cost-sharing that may lead to unexpected expenses or delays in care, which some beneficiaries don’t realize until they need frequent or specialized services.
The Initial Appeal of Medicare Advantage
When you first become eligible for Medicare, the two main paths you can take are Original Medicare with a Medicare Supplement, or a Medicare Advantage plan. Many people gravitate toward Medicare Advantage plans because of their bundled coverage, added extras, and what appears to be low upfront costs. However, these advantages often come with significant trade-offs that may not become clear until later.
Medicare Advantage plans are run by private insurance companies approved by Medicare. They must provide at least the same coverage as Original Medicare Parts A and B, but they can set their own rules about how you access care. That includes networks, referrals, prior authorization requirements, and cost-sharing.
In 2025, over half of all Medicare beneficiaries are enrolled in Medicare Advantage. But a growing number of them report dissatisfaction after encountering higher-than-expected out-of-pocket costs or limited access to care.
What Changes After the First Year Matters
You have a one-time Medigap open enrollment window that starts the month you’re both 65 or older and enrolled in Medicare Part B. During this six-month window, you can buy any Medicare Supplement policy sold in your state without being denied coverage or charged more due to health conditions.
However, after this period ends, most states allow Medigap insurers to use medical underwriting. This means if you want to switch from Medicare Advantage to a Supplement later on, you might have to answer health questions, face higher premiums, or be denied coverage altogether.
This becomes a major roadblock for those who develop health issues and want the broader access or predictable costs of a Medigap plan. While some states offer additional guaranteed issue rights, they are limited in scope and vary widely.
Why Some Enrollees Feel Stuck
People who enroll in Medicare Advantage often assume they can switch later if they become dissatisfied. Technically, you can switch during the Medicare Advantage Open Enrollment Period (January 1 to March 31) or the Annual Enrollment Period (October 15 to December 7). But switching from Advantage to Original Medicare doesn’t guarantee you can get a Medigap policy without medical underwriting.
This can leave you with a choice between:
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Staying in Medicare Advantage despite problems like network restrictions or denied services
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Returning to Original Medicare but being exposed to unlimited 20% coinsurance without a Medigap plan to help cover it
That sense of being “locked in” can lead to regret, especially when health needs become more complex.
Network Restrictions and Limited Access to Specialists
Unlike Original Medicare, which allows you to see any provider who accepts Medicare nationwide, Medicare Advantage plans typically use provider networks. If you go out-of-network, you may pay more or have no coverage at all, depending on the plan.
This model works for some people who don’t travel or who have all their providers within the same system. But if you:
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Move to a different state
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Travel seasonally
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Need a specialist outside your local area
…you might find your access to care severely limited. Many enrollees don’t realize this limitation until they need specific types of care.
Prior Authorizations and Delayed Care
As of 2025, Medicare Advantage plans still widely use prior authorization requirements. That means you or your doctor need to get approval from the plan before certain tests, procedures, or specialist visits are covered.
According to recent federal data, millions of prior authorization requests are submitted each year, and many are denied or delayed. While some are later overturned on appeal, the delays can cause anxiety and even medical complications.
Original Medicare does not require prior authorizations for most services. Many people only discover this distinction after facing repeated hurdles under an Advantage plan.
Cost-Sharing That Adds Up Quickly
Although many Medicare Advantage plans advertise low premiums, they typically involve:
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Copayments for office visits, specialists, and urgent care
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Coinsurance for outpatient services, surgeries, or hospital stays
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Deductibles for certain types of care
There are annual out-of-pocket maximums that cap what you pay for covered services. In 2025, the maximum for in-network care is $9,350. However, this does not include prescription drugs, which are subject to separate out-of-pocket costs under Part D.
With frequent medical needs, these costs can add up rapidly. In contrast, Medigap policies offer more predictable spending by covering most or all of Original Medicare’s cost-sharing.
Difficulties With Reenrollment in Medigap
Let’s say you want to switch from Medicare Advantage back to Original Medicare and add a Medigap policy. In many cases, the timeline works against you:
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Outside your six-month Medigap Open Enrollment, you may face medical underwriting
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Some plans may deny coverage for preexisting conditions or impose waiting periods
The assumption that you can always switch back with ease is one of the biggest misconceptions that leads to regret. Unlike Medicare Advantage, Medigap plans don’t have an annual open enrollment period.
Limited Emergency Coverage Outside the U.S.
Original Medicare typically doesn’t cover care outside the United States. But some Medigap plans include emergency foreign travel coverage up to plan limits.
Most Medicare Advantage plans do not cover medical care received abroad, or they offer minimal emergency coverage. For retirees who travel internationally, this lack of protection can be a deciding factor.
When You Can Change Without Underwriting
There are specific situations where you can switch to a Medigap plan with guaranteed issue rights, even outside the usual enrollment period. For example:
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If your Medicare Advantage plan leaves your area
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If you move out of your plan’s service area
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If your Advantage plan violates its contract with you
These special circumstances can offer another chance to get Medigap without health questions, but they don’t apply to most people who simply want to change plans.
Making the Right Choice the First Time
The best time to choose between Medicare Advantage and Medigap is when you are first eligible for Medicare. Consider the following questions carefully:
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Do you prefer to see any doctor or specialist without referrals?
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Are you comfortable with managed care and provider networks?
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Would you rather have lower monthly costs now or more predictable expenses long term?
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Do you expect to travel, live in multiple states, or seek specialty care?
It’s easier to go from Medigap to Medicare Advantage than the other way around. That’s why many people who prioritize flexibility and coverage stability from the start lean toward Medigap.
Growing Awareness and Regulatory Changes
In recent years, federal agencies have increased oversight of Medicare Advantage plans due to complaints about marketing, denied care, and plan complexity. While regulators are working to improve transparency, the core structure of Advantage plans remains unchanged in 2025.
Consumer awareness is increasing, and more people are asking critical questions before enrolling. But for many, those questions come too late—after they’ve already committed to a plan that doesn’t meet their needs long-term.
Why This Decision Deserves Extra Attention
Choosing between Medicare Advantage and a Supplement isn’t just about monthly costs. It affects where you can get care, how much you pay out of pocket, and whether you can change your mind later without obstacles.
Every year, enrollment periods give you opportunities to review your coverage. But switching between systems isn’t always smooth. The decision you make when you first sign up can follow you for years.
Talk to someone who understands the system. A licensed agent listed on this website can help you weigh your options based on your health, travel plans, and budget goals.
Let Your Medicare Choices Support Your Future
When your health and lifestyle evolve, your Medicare coverage should be able to keep up. That flexibility is often harder to find once you’re in a Medicare Advantage plan and trying to switch.
If you haven’t enrolled yet or are still within your one-time Medigap Open Enrollment period, consider all your options now—before health or time limits your choices. And if you’re already enrolled and concerned about your plan, speak with a licensed agent listed on this website to explore whether a change makes sense.
