Two different systems, one decision — and a window that closes quietly at the six-month mark.
Key takeaways
- Original Medicare with Medigap means no networks and predictable costs; Medicare Advantage means lower premiums with networks and prior authorization.
- After the 6-month Medigap Open Enrollment Period, insurers in most states can underwrite you, so switching back from Advantage may not be possible.
- Check your doctors against any Advantage network and your prescriptions against each formulary, and if you lean Medigap, act inside the window.
What are the two paths?
Once you have Parts A and B, you choose a lane. Either Original Medicare, usually with a Medigap supplement and a separate Part D drug plan — or Medicare Advantage, a private plan that bundles it together.
How does Original Medicare + Medigap work?
- Any doctor or hospital in the country that accepts Medicare. No networks.
- No referrals to see a specialist.
- Medigap covers most of what Original Medicare leaves — deductibles and coinsurance.3
- You pay a Medigap premium on top of Part B, plus a separate Part D plan.
- Costs are predictable — higher monthly, lower surprise.
How does Medicare Advantage work?
- Premiums vary by plan. Some charge $0 beyond your Part B premium, and plans can include drug coverage.5
- Extras Original Medicare doesn't cover — dental, vision, hearing, sometimes a grocery benefit.
- But: networks. Your doctors must be in-plan, and networks change.
- Prior authorization — the plan can require approval before certain care.4
- Copays as you use care, up to an annual out-of-pocket maximum.4
What is the real trade-off?
What is the window nobody warns you about?
Here is the part that makes this close to permanent. You get a 6-month Medigap Open Enrollment Period, starting the first month you are 65 or older and enrolled in Part B.2
During those six months you have a guaranteed issue right: any Medigap policy sold in your state must accept you, at the standard price, regardless of your health.2
What should you do next?
- List your doctors and check them against any Advantage network you're considering.
- List your prescriptions and check each plan's formulary.
- Ask honestly how your health may look in ten years, not just today.
- If you lean Medigap, act inside the six-month window.
Sources
- medicare.gov — Medicare & You 2026
- medicare.gov — When can I buy a Medigap policy
- medicare.gov — Medigap basics
- medicare.gov — Understanding Medicare Advantage
- medicare.gov — Medicare costs
Medicare vs. Medigap
The side-by-side comparison, the questions to ask, and the window that closes at six months.
Next Chapter Today is not a government website and is not affiliated with the Social Security Administration or any agency. This article is educational and is not individualized legal, medical, tax or financial advice. Confirm your own figures with the agency before you act.
