Many of us dislike surprises. That is why it is important to understand some of the changes coming to Medicare Part D before the Dec. 7 deadline. Step one, track down your "Annual Notice of Change." That is the "heads up" your provider sends out about the upcoming year. The first change you may notice: many Part D plans are ending or merging. Out-of-pocket costs for the voluntary prescription coverage will also be capped at $2,000 in 2025.  Gap coverage, nicknamed donut hole coverage, will also be going away for everyone next year.