Medicare Part D Articles & Guides

Plain-English guides to Part D costs, enrollment periods, formularies, and plan choices — updated regularly.

Costs

90-Day Supplies: When They Save You Money in Part D

A 90-day supply can cut your prescription costs by a third or more — but not every drug qualifies. Learn when longer fills save money, mail-order rules, and what to watch for in 2026.

2026-10-19
Costs

Preferred vs. Standard Pharmacies in Part D

Why does your copay change between pharmacies? Learn how Part D preferred vs. standard pharmacy networks work, how much you can save, and how to check before you fill.

2026-10-18
Costs

Mail-Order Pharmacy in Part D: Savings and Rules

Most Part D plans offer 90-day mail-order prescriptions, often cheaper than three retail fills. Learn how mail-order savings work, which drugs qualify, and the rules to know.

2026-10-17
Enrollment

Moving to a New State? Your Part D Plan Explained

Moving to a new state can leave your Part D plan behind — drug plans only cover their service area. Learn how the move SEP works, when to switch, and how to keep prescriptions covered.

2026-10-04
Coverage

Part D Vaccines at $0 in 2026: What's Covered

Medicare Part D covers adult vaccines recommended by the CDC at $0 in 2026 — no copay, no deductible. Learn which vaccines are covered, where to get them, and how to avoid surprise bills.

2026-09-27
Costs

Part D vs. GoodRx: Can You Use Both in 2026?

Can you use GoodRx with Medicare Part D? Yes — but not on the same fill. Here's how the rules work, when discount prices beat your copay, and the $2,100 cap trade-off to know first.

2026-09-21