If you have a Medicare Supplement (Medigap) plan, you’re probably confident that your medical expenses are well covered. But many people forget that prescription drug coverage—through a standalone Part D plan—is a separate piece entirely. And if you’re not reviewing that plan each year, you may experience some unexpected costs.
Take Mark and Susan, for example. Their Medicare and Supplement plan were set up and running smoothly. But when Susan was prescribed a new medication after a diagnosis, they discovered it wasn’t covered under their Part D plan’s formulary. Because the drug wasn’t on the plan’s list of covered medications, the out-of-pocket cost was significantly higher than expected.
While Part D plans now include an annual out-of-pocket cap of $2,100 (in 2026) on covered drugs, that protection only applies to medications your plan covers. If a drug is removed from the formulary or was never included, you may be responsible for the full retail cost — which is why reviewing your plan’s drug list each year is so important.
Part D plans change every year, and so do your medications. Each fall, your insurance company is required to send a letter called the Annual Notice of Change (ANOC). This document outlines exactly what will be different in your plan for the upcoming year—drug coverage, costs, pharmacy networks, and more.
The Cost of “Set It and Forget It”
Many people assume once they pick a Part D plan, they’re set. But drug plans change every year. Formularies shift. Pharmacies change. Tiers are adjusted. And your health? That evolves too.
If you don’t review your plan—and your ANOC—regularly, you could be paying more than necessary or find yourself without coverage when it matters most.
What Changes in a Part D Plan Each Year?
Even if your prescriptions stay the same, your plan might not. Here are just a few examples of what can change from year to year and will be listed in your ANOC:
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Drug coverage (formulary): Medications may be dropped or moved to a more expensive tier
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Cost-sharing: Copays and coinsurance rates can change
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Pharmacy networks: Your preferred pharmacy may no longer be in-network
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Premiums: Monthly costs can change
That’s why a quick annual review is one of the smartest things you can do to protect yourself—and your budget.
How to Review Your Plan in 15 Minutes or Less
You don’t need to wait until Annual Enrollment to take a look. In fact, the sooner you know whether your plan is still a good fit, the more prepared you’ll be when switching is allowed.
Here’s how to get started:
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Make a list of your current prescriptions, including dosages and frequency.
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Read through your ANOC when it arrives in September to see what’s changing for next year.
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Visit Medicare.gov and use the Plan Finder Tool to enter your medications and preferred pharmacy.
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Compare your current plan to others available in your area. Pay attention to drug costs, pharmacy access, and total annual out-of-pocket estimates.
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Take notes and flag any concerns to revisit during the Annual Enrollment Period (October 15–December 7).
It’s quick and it’s free.
Don’t Let a Silent Change Become a Major Expense
Reviewing your ANOC and comparing your plan each year isn’t just about finding the lowest premium. It’s about making sure your medications are still covered, your pharmacy still works with your plan, and your overall costs are as low as they can be. A little effort now can prevent a financial shock later.
We’re Here to Help You Make Sense of It
If your prescriptions have changed, or you just haven’t looked at your drug plan in a while, we are here to help.