Medicare 2026

Idaho Falls Guide to Medicare Part B and Part D Sign-Up Windows

IDAHO FALLS, Idaho — Miss the wrong Medicare sign-up window and you could pay extra every single month for the rest of your life. That is the hard truth behind the late-enrollment penalties tied to Medicare Part B (doctor visits and outpatient care) and Part D (prescription drugs). The good news: these penalties are avoidable if you know the deadlines and act on time.

Why these penalties exist

Medicare is built on the idea that everyone pays in. If people waited to enroll only when they got sick, premiums would climb for everyone else. To keep the system balanced, Congress created lifelong penalties for people who delay Part B or Part D without a good reason, like having creditable coverage from an employer.

That means the enrollment rules are not just paperwork — they are financial deadlines with a long tail.

The Part B late-enrollment penalty

If you don't sign up for Part B when you're first eligible, and you don't have other coverage that counts, your monthly premium can go up 10% for each full 12-month period you were eligible but didn't enroll.

That extra amount is added to your standard Part B premium for as long as you have Part B — in most cases, for the rest of your life. Someone who waits three full years, for example, could pay 30% more every month, permanently.

Your Initial Enrollment Period is a seven-month window: the three months before the month you turn 65, your birthday month, and the three months after. If you miss it, you may have to wait for the General Enrollment Period (January 1 – March 31) to sign up, with coverage starting the month after enrollment.

The Part D late-enrollment penalty

The Part D penalty works a little differently. If you go 63 days or more in a row without Part D or other "creditable" drug coverage after your Initial Enrollment Period ends, Medicare can charge a penalty when you eventually enroll.

The math: 1% of the "national base beneficiary premium" is multiplied by the number of full months you went without coverage, then rounded to the nearest 10 cents. That amount is added to your Part D premium — again, for as long as you have Part D.

Creditable coverage means drug coverage that Medicare considers at least as good as standard Part D. Employer plans, union plans, and VA benefits often qualify, but not always. Keep any letter your plan sends you each year confirming this status — you may need it later to prove you shouldn't be penalized.

Special Enrollment Periods can save you

Not everyone signs up at 65, and that's okay if you qualify for a Special Enrollment Period (SEP). The most common reason: you (or your spouse) were still working and covered by a group health plan based on that job.

When that coverage ends, you generally have eight months to enroll in Part B without a penalty, and 63 days to pick up Part D coverage. Retiree coverage and COBRA usually do not count as active employment for Part B purposes — a common and costly mix-up. If you're unsure, ask before you drop anything.

What Idaho Falls residents can do now

Idaho Falls is in Bonneville County, where residents have access to Original Medicare plus a range of Medicare Advantage and stand-alone Part D plans sold by private insurers. The number of options changes each year, but the enrollment deadlines do not.

A few practical steps:

• Mark your calendar. Note your 65th birthday month and count back three months — that's when your Initial Enrollment Period opens.
• Check your current coverage. If you have drug coverage through work, a union, or the VA, confirm in writing that it's creditable.
• Use free help. Idaho's State Health Insurance Assistance Program (SHIBA) offers unbiased, one-on-one counseling at no cost. You can also call 1-800-MEDICARE or visit medicare.gov.

For 2026, remember that Part D also comes with a new $2,100 out-of-pocket cap on covered drugs and a maximum deductible of $615 — protections that only help if you're actually enrolled.