How Medicare works alongside employer coverage: enrollment timing at 65, who pays first, Part D creditable coverage, and HSA rules for employees who keep working.
Yes. If a major life-changing event lowered your income, you can ask Social Security to recalculate your IRMAA using more recent income, with Form SSA-44. Qualifying events include marriage, divorce, the death of a spouse, work stoppage, and loss of income.
No. You cannot use both at once, and it is illegal for an insurer to sell you Medigap while you are in a Medicare Advantage plan unless you are switching back to Original Medicare.
If you do not sign up for Part B when first eligible and have no Special Enrollment Period, your premium rises 10% for each full 12 months you could have had it, usually for as long as you have Part B.
The best time is your six-month Medigap Open Enrollment Period, which begins the first month you are 65 or older and enrolled in Part B. During that window an insurer cannot deny you or charge more based on your health; afterward, it usually can.
IRMAA is an extra amount higher-income beneficiaries pay on top of their Medicare Part B and Part D premiums. For 2026 it starts when income (from your 2024 tax return) exceeds about $109,000 for individuals or $218,000 for couples.
When you retire, your active employer coverage usually ends, which triggers an 8-month Special Enrollment Period to sign up for Medicare Part B without penalty. Some employers offer retiree coverage or an HRA that works alongside Medicare.
It depends on employer size. If your (or your spouse’s) employer has 20+ employees, that plan usually pays first and you can delay Part B without penalty. If the employer has fewer than 20 employees, Medicare typically pays first, so you generally should enroll in Part B at 65.
Medicare Advantage (Part C) replaces Original Medicare with a private plan that has networks and often extra benefits, usually at a low premium. Medigap works alongside Original Medicare to pay its out-of-pocket costs and lets you see any Medicare provider, but costs more in premium.
Your first chance is the 7-month Initial Enrollment Period around your 65th birthday. After that, the Annual Enrollment Period (Oct 15 to Dec 7) lets you change Medicare Advantage and Part D plans, and Special Enrollment Periods apply after events like leaving employer coverage.
Part A covers hospital/inpatient care, Part B covers doctors and outpatient care, Part C (Medicare Advantage) is a private all-in-one alternative to A and B, and Part D covers prescription drugs.
Lower-income beneficiaries can get major help. Extra Help (the Part D Low-Income Subsidy) cuts prescription costs, and Medicare Savings Programs help pay Part B premiums and other costs. In 2026, Extra Help covers full premiums (up to the benchmark) and caps drug copays at $5.10 generic and $12.65 brand.
Original Medicare generally does not cover routine dental, vision, or hearing care, hearing aids, most long-term custodial care, or care outside the U.S. Some Medicare Advantage plans add dental, vision, and hearing benefits.
No. Under the Medicare Secondary Payer rules, an employer with 20 or more employees cannot require, pressure, or financially incentivize a Medicare-eligible active employee to drop the group plan in favor of Medicare. Doing so can trigger a civil money penalty of $11,823 per violation in 2026.
Creditable coverage is employer drug coverage that’s at least as good as standard Medicare Part D. Employers that cover Medicare-eligible people must tell them whether their drug coverage is creditable before October 15 each year, and must disclose creditable/non-creditable status to CMS within 60 days of the plan year start.
For active employees 65+, the employer plan pays first if the employer has 20 or more employees, with Medicare second. If the employer has fewer than 20 employees, Medicare pays first. Disability-based Medicare uses a 100-employee threshold, and ESRD has its own 30-month coordination period.
It depends on your employer’s size. If your employer has 20 or more employees and you have active group coverage, you can usually delay Medicare without penalty. If the employer has fewer than 20 employees, Medicare generally pays first, so you should enroll at 65 to avoid gaps and penalties.
The Part D late enrollment penalty is a permanent surcharge added to your Part D premium if you go 63 or more days without creditable drug coverage after your initial enrollment period. It’s roughly 1% of the national base premium for each month you went without, for as long as you have Part D.
No. Once you enroll in any part of Medicare, including premium-free Part A, you can no longer contribute to an HSA, though you can still spend the existing balance. To keep contributing while working past 65, you must delay all of Medicare, which usually means not claiming Social Security.