Every year everyone participating in a Part D Prescription Plan will receive an Annual Notice Of Change from the company with whom they have the coverage.
Pay attention to premium, copay, drug tiers, and the formulary. A formulary is the list of generic and brand-name prescription drugs covered by a specific health insurance plan. This will let you know if your medication is still covered.
In 2023 for example a brand name Tier 5 medication is going to have a 25% co-pay. If you have a prescription that costs $1500 monthly your portion would be $125.00 each month.
So pay attention to all the plan details so you understand what your actual out of pocket spending is going to be.