Medicare 2026

Medigap or Medicare Advantage? Watch These Key Dates

Essex Junction, Vt. — For older adults here weighing how to get their Medicare coverage, the choice between Original Medicare paired with a Medigap policy and a Medicare Advantage plan often comes down to more than benefits on paper. It comes down to the calendar. Miss the right window, and the door to one path can quietly close — or reopen only with strings attached.

Essex Junction is in Chittenden County, where residents choose between two very different structures. Original Medicare (Parts A and B) is the federal program, and many people add a stand-alone Part D drug plan plus a Medigap policy to help with the out-of-pocket costs Original Medicare leaves behind. Medicare Advantage (Part C) is different: private plans that replace how you receive your Parts A and B benefits, usually bundling drug coverage and using a network.

Both paths are governed by strict enrollment windows. Here is how those dates line up, and what happens if one slips by.

The two structures, in plain terms

Original Medicare plus Medigap is the "pay-as-you-go federal program with a private supplement" model. Medicare pays its share, then your Medigap policy picks up much of what's left, depending on the standardized plan letter you buy. You typically add a separate Part D drug plan.

Medicare Advantage is the "all-in-one private plan" model. You still have Medicare, but a private insurer administers your Part A and Part B benefits, usually adds Part D, and often includes extras. Networks, prior authorization, and referral rules vary by plan.

The structural difference matters most when your health changes — and when the enrollment calendar comes around.

The Medigap window most people don't get back

The single most important date for anyone considering the Original Medicare + Medigap path is the Medigap Open Enrollment Period. It is a one-time, six-month window that starts the month you are both 65 or older and enrolled in Part B. During that window, insurers must sell you any Medigap policy they offer, at their best available rate, regardless of your health history.

After that window closes, federal law no longer guarantees you that right in most situations. Insurers in most states — Vermont included, with limited exceptions — can use medical underwriting, which means they can charge more or decline to sell you a policy based on your health.

That is why the Medigap window is the deadline Essex Junction readers should mark first. It doesn't come back next fall.

The Annual Enrollment Period: Oct. 15 – Dec. 7

Each year, the Annual Enrollment Period (AEP) is when most Medicare decisions get made. During AEP you can:

• Switch from Original Medicare to a Medicare Advantage plan, or vice versa.
• Join, drop, or change a Part D drug plan.
• Change from one Medicare Advantage plan to another.

Changes made during AEP take effect Jan. 1. Miss AEP and, outside of narrow special circumstances, you generally wait a full year for another chance to change your Advantage or Part D plan.

Important caveat: leaving Advantage for Original Medicare during AEP does not guarantee you can then buy a Medigap policy. That is a separate question governed by Medigap rules.

The Medicare Advantage Open Enrollment Period: Jan. 1 – March 31

If you're already in a Medicare Advantage plan on Jan. 1 and it isn't working out, you get a second chance. The Medicare Advantage Open Enrollment Period lets you make one change: switch to a different Advantage plan, or drop Advantage and return to Original Medicare (with the option to pick up a Part D plan).

This window is only for people already in Advantage. If you're in Original Medicare, it does not apply to you. And again, returning to Original Medicare during this window does not automatically hand you Medigap rights.

When windows are missed

Missing a window doesn't always mean you're stuck forever, but it usually costs you options.

• Missed your Medigap open enrollment? You can still apply, but insurers in most states can underwrite.
• Missed the AEP? You generally wait until next Oct. 15, unless a Special Enrollment Period applies (a move, loss of other coverage, qualifying for Extra Help, etc.).
• Missed Part B enrollment when you first became eligible? You may face a lifelong late-enrollment penalty, and you'll enroll during the General Enrollment Period (Jan. 1 – March 31).
• Went without creditable drug coverage? A Part D late-enrollment penalty can be added to your premium for as long as you have Part D.

How the Part D changes fit in for 2027

Whichever path you choose, drug coverage rules keep evolving. The Part D out-of-pocket cap is $2,100 in 2026 and rises to $2,400 in 2027. The maximum Part D deductible is $615 in 2026 and $700 in 2027. The old coverage gap ("donut hole") has been gone since 2025. The optional Medicare Prescription Payment Plan lets you spread drug costs across the calendar year in monthly installments.

Higher earners should also know about IRMAA — income-related monthly adjustment amounts that increase Part B and Part D premiums for single filers with income above $109,000 in 2026.