8 Medicare Enrollment Mistakes That Cost North Carolinians All Year

Do you think signing up for Medicare is as simple as turning 65 and mailing in a form?

Not necessarily.

These are the Medicare enrollment mistakes that cost North Carolinians and retirees across the U.S. all year.

Note: This is general information, not financial, insurance, or medical advice. Enrollment rules and dollar amounts are subject to change, so confirm the current details at Medicare.gov.

1. Missing the Initial Enrollment Window

Medicare’s Initial Enrollment Period runs seven months for many people, the three months before their 65th birthday month, that birthday month, and the three months after it.

If you miss that window without other coverage lined up, you pay for it.

Medicare tacks on an extra 10% to the Part B premium for every full 12-month period without coverage.

The penalty is permanent.

The surcharge adds to the standard Part B premium, which is $202.90 a month in 2026.

That charge follows someone for as long as they carry Part B.

A retiree who waited two full years to enroll pays 20% more than everyone else on the same coverage, every month.

For many people, that extra cost lasts for life.

2. Trusting COBRA to Buy Time

COBRA, the federal law that lets someone keep their old job’s health plan for up to 18 months after they leave, has one big catch once Medicare enters the picture.

Medicare doesn’t count COBRA as coverage that delays enrollment.

The eight-month Special Enrollment Period to sign up for Part B starts the day active employment ends, not the day COBRA runs out.

Someone who rides out a full 18 months of COBRA before enrolling has already blown past that deadline by ten months.

That’s ten months lost.

That gap becomes a permanent penalty stacked on every Part B bill that follows.

3. Skipping Part D Too Early

Medicare Part D covers prescription drugs, and many healthy new enrollees skip it on purpose because they don’t take any medication yet.

That’s a costly bet.

Someone who goes 63 days or more without Part D or other creditable drug coverage owes a penalty.

Medicare adds an extra 1% of the national base beneficiary premium, $38.99 in 2026, for every month without coverage.

Medicare adds that penalty to the monthly Part D bill for as long as the person has drug coverage, even after switching plans.

Fourteen months without coverage works out to a permanent 14% surcharge on top of whatever plan comes next.

4. Small-Employer Blind Spot

Medicare works differently if you keep working past 65, depending on the size of the employer providing your health plan.

Once that employer has fewer than 20 employees, Medicare becomes the primary payer and the employer’s plan pays second, whether or not the employee has signed up for Part B.

Skip Part B in that setup, and your employer’s plan may cover only a small slice of a hospital bill.

The rest lands on you.

Workers at a company that size have to enroll in Part B at 65, or within eight months of leaving that job, whichever comes first.

Otherwise, they face the same lifetime penalty every other late enrollee pays.

5. Letting the Medigap Window Close

Medigap policies help cover the gaps Original Medicare leaves behind, like coinsurance and deductibles.

Federal law hands every new enrollee a one-time window to buy one without a health screening.

That window is six months long, starting the first month a person has Part B and is 65 or older.

An insurer can run a full medical underwriting review on anyone who misses that window, charging more for a pre-existing condition or turning the application down outright.

There’s no second chance later.

North Carolina runs a free program through the state Department of Insurance called the Seniors’ Health Insurance Information Program, or SHIIP.

Volunteer counselors in every county walk residents through that six-month window before it closes.

Waiting past that six-month mark can mean paying more for the exact same Medigap coverage every year afterward, if a company agrees to sell it at all.

6. Missing the Trial-Right Deadline

Medicare Advantage plans replace Original Medicare with a private plan, and federal rules give first-time enrollees a safety net if the switch doesn’t work out.

That safety net is called a trial right.

Someone who joins Medicare Advantage the first time they’re eligible for Medicare has 12 months from that plan’s start date to drop it.

They can buy any Medigap policy sold in their state on a guaranteed-issue basis in that window, no health questions asked.

That guarantee expires 63 days after the trial year ends.

There’s only one shot.

After that, the same medical underwriting from the Medigap window applies, and an insurer can charge a retiree with a health condition more, or turn them away for good.

7. Skipping an IRMAA Appeal

Medicare charges some higher earners an Income-Related Monthly Adjustment Amount, or IRMAA, on top of the standard Part B and Part D premiums.

In 2026, that surcharge kicks in once income crosses $109,000 for a single filer or $218,000 for a couple.

At the first tier, the Part B premium jumps from $202.90 to $284.10 a month.

The catch is the timing.

Social Security bases this year’s IRMAA on a tax return from two years back.

A retiree who sold a house or cashed out an account in 2024 can carry that higher bill well into 2026.

The Social Security Administration lets you request a lower amount after a life-changing event, like retirement, divorce, or the death of a spouse.

That relief comes through Form SSA-44, but only for people who ask.

8. Skipping the Annual Plan Review

Medicare Advantage and Part D plans aren’t locked in place year after year.

Premiums, drug formularies, and provider networks can all change on January 1.

A plan that fit perfectly last year can turn expensive with little warning beyond a mailed booklet.

Open Enrollment runs October 15 through December 7 every year.

It’s the one chance to switch to a better-fitting plan before next year’s terms take hold.

Skip that window, and the current plan carries over as-is.

Those changes apply either way.