Updated July 2026 · Reviewed by the CoverageCo team
The main trade-offs are provider networks, prior authorization requirements, referral rules, limited coverage when you travel, and the difficulty of switching to Medigap later. None of these make Advantage a bad choice — but each one is a real constraint that catches people who enrolled based on premium alone.
Key takeaways
- Networks are the most common regret — check your doctors before anything else.
- Prior authorization can delay or deny services that Original Medicare would simply cover.
- Coverage while traveling or living part of the year elsewhere can be limited.
- Switching back to Medigap later may require passing medical underwriting, and you can be declined.
Networks are the constraint people feel first
Most Advantage plans only pay in full for care from providers in their network. If your longtime doctor or preferred hospital system isn't in it, you either change doctors or pay considerably more.
Networks also change. A provider who's in-network this year may not be next year, and plans can adjust their networks mid-year. This is the single most common source of Advantage regret, and it's entirely avoidable by checking before you enroll.
Prior authorization adds a gatekeeper
Advantage plans commonly require prior authorization for certain services — imaging, some procedures, skilled nursing stays, durable medical equipment.
That means the plan reviews whether it considers the service necessary before it agrees to pay. Most requests are approved, but the process can introduce delay, and denials do happen for care that Original Medicare would have covered without the extra step.
You can appeal, and appeals frequently succeed. But it's work, and it tends to arrive when you're least equipped to handle it.
Travel and part-year living can get complicated
If you split the year between states, or travel often, network rules can become genuinely inconvenient. Emergency care is covered wherever you are, but routine and follow-up care generally isn't handled the same way outside your plan's service area.
Original Medicare with a Medigap policy travels with you — any provider nationwide who accepts Medicare accepts it. For snowbirds and frequent travelers, that difference often outweighs the premium savings.
The switching problem is the one to think hardest about
This is the trade-off with the longest tail, and it deserves more weight than it usually gets.
You can generally move from Medigap to Advantage without difficulty. Moving the other direction is different: outside your one-time Medigap open enrollment window or a limited set of guaranteed-issue situations, most states let insurers review your health and decline you.
In practice, someone who chooses Advantage at 65, develops a condition at 72, and then wants the predictability of Medigap may find the door has quietly closed. Choose knowing that asymmetry exists, not after discovering it.
So should you avoid Medicare Advantage?
No — and that's not what this page argues. Millions of people are well served by Advantage plans, particularly those who are comfortable in a network, want lower monthly costs, and value the bundled extras.
The point is that these trade-offs are structural, not marketing spin. Anyone selling you an Advantage plan without mentioning networks, prior authorization, or the switching asymmetry isn't giving you the full picture.
Compare with your actual doctors and prescriptions in hand, and weigh how much predictability is worth to you personally.
Common questions
Can I switch from Medicare Advantage back to Original Medicare?
You can return to Original Medicare during the appropriate enrollment window. The harder part is adding a Medigap policy afterward — outside your one-time Medigap open enrollment or a guaranteed-issue situation, most states allow insurers to medically underwrite you and decline coverage.
Do Medicare Advantage plans cover care out of state?
Emergency and urgent care is covered wherever you are. Routine and follow-up care outside the plan's service area generally is not covered the same way, which matters if you travel often or live part of the year elsewhere.
Why do some Medicare Advantage plans cost $0 per month?
The plan's own premium can be $0 because Medicare pays the insurer to administer your benefits. You still pay your Part B premium, plus copays and coinsurance when you use care.
Does Medicare Advantage require referrals?
It depends on the plan type. HMO plans usually require a referral from your primary care doctor to see a specialist. PPO plans usually don't, though out-of-network care costs more.