How to Compare Medicare Part D Plans

Almost always because the plan year reset. Every January you start over in the deductible stage and pay the full negotiated price for your drugs until the deductible is met — no plan can charge a deductible over $615 in 2026, but you can hit all of it in one January fill. The other two common causes are the plan moving the drug to a higher cost tier, or dropping it from the formulary entirely. Costs drop once the deductible is satisfied, and covered drugs cost nothing at all once out-of-pocket spending reaches $2,100 in 2026.

Yes, and it’s more common than people expect. A Medicare drug plan can change its drug list at any time under Medicare’s guidelines, though the plan must notify you of changes affecting drugs you’re taking. Your move is to ask for an exception: you or your prescriber request it, and your prescriber submits a statement explaining the medical reason. You can also request a tiering exception to get a lower copay on a drug sitting on a non-preferred tier.

For most people you wait for Open Enrollment, October 15 to December 7, with the new plan starting January 1. If you’re already in a Medicare Advantage plan, you also get January 1 to March 31 to switch plans or return to Original Medicare and pick up a standalone drug plan. Outside those windows you need a Special Enrollment Period, which certain life events trigger — moving, losing your current coverage, getting Medicaid, or qualifying for Extra Help.

In most cases yes — because the penalty for skipping it never goes away. If you go 63 days or more without creditable drug coverage after you’re first eligible, you pay an extra 1% for every month you went without, calculated from the national base beneficiary premium ($38.99 in 2026), and that amount is added to your premium for as long as you have Medicare drug coverage, even if you switch plans. You’re exempt if you have creditable coverage from another source, or if you qualify for Extra Help. A low-premium plan you barely use is usually cheaper than the permanent penalty.

There’s a real program and the limits are higher than most people assume. Extra Help pays Part D premiums, deductibles and cost sharing; in 2026 you may qualify with income up to $23,940 and resources up to $18,090 as an individual, or $32,460 and $36,100 as a married couple. Under Extra Help in 2026 you pay a $0 premium, a $0 deductible, and no more than $5.10 for a generic or $12.65 for a brand-name drug. You also can’t be charged a Part D late enrollment penalty while you have it. You apply through Social Security, and a free SHIP counselor will help you fill it out.

Usually not — that’s the single most expensive habit in open enrollment. A rock-bottom premium is often paid for by a formulary that puts your specific drug on a high tier, or leaves it off, so the plan that looked cheapest in October becomes the most expensive by June. Enter your actual medications and your actual pharmacy into the Medicare Plan Finder and sort by total estimated yearly cost. Premium is one of four moving parts, and it’s the one that matters least.

Ask your plan about the Medicare Prescription Payment Plan. It lets you spread your out-of-pocket Part D costs across monthly payments over the calendar year instead of paying a large amount at the counter up front. It does not lower what you owe in total — it changes the timing, which is exactly the problem when an expensive drug lands in January. You opt in through your drug plan, not through Medicare.

Often it is covered, and you’ve just hit a plan rule instead. Plans commonly require prior authorization, step therapy (trying a cheaper drug first), or quantity limits before they’ll pay. Each of these can be appealed with an exception request, and your prescriber has to supply a statement — that the drug is medically necessary for you, that a different drug would be less effective, or that you’d have negative health effects on the alternative. When new coverage starts, you may also get a one-time 30-day transition fill while this gets sorted out.