Your fall coverage calendar: the dates that matter between now and January 1

Nothing on this list requires action today. But every fall, people discover a deadline two weeks too late — so here's the whole sequence in one place, using the statutory windows that hold every year.

Late September: the letter worth opening

If you're on a Medicare Advantage or Part D plan, your plan mails an Annual Notice of Change (ANOC) around late September. It lists exactly what changes January 1: premium, copays, drug list, network. It's the single most useful piece of insurance mail you'll get all year, and most people don't open it. Open it — it tells you whether the next date on this calendar matters to you.

October 15 – December 7: Medicare's Annual Enrollment Period

The AEP is when anyone on Medicare can switch Medicare Advantage plans, move between Original Medicare and Medicare Advantage, or change Part D drug plans. Changes take effect January 1. If your ANOC showed your plan getting worse for how you actually use it — a drug moving tiers, a doctor leaving network — this is the window to compare what else is available where you live. If your plan still fits, doing nothing keeps it.

November 1: marketplace Open Enrollment begins

For individual and family coverage, Open Enrollment starts November 1 in most states for coverage starting January 1 (enrollment deadlines for January 1 coverage vary; many states use December 15, and some state exchanges run longer overall). After the window closes, you'll generally need a qualifying event to enroll. If your income changed this year, re-checking your tax credit during Open Enrollment is worth the ten minutes even if you keep the same plan.

January 1 – March 31: the do-over window

Two useful January facts. Everything you chose in the fall takes effect January 1. And if you're in a Medicare Advantage plan that turns out wrong, the Medicare Advantage Open Enrollment Period (January 1 – March 31) allows one switch to another MA plan or back to Original Medicare. It's a real safety valve — but only for people already on Medicare Advantage.

What to do in August

Honestly? Almost nothing — just calendar it. When the ANOC arrives, read it. If anything in it surprises you, the AEP gives you eight weeks to act, and a licensed agent can compare your options with you for free. The people who get squeezed are the ones who start on December 6.