What if I have a health savings account at work?
You need to be careful if your employer insurance takes the form of a high-deductible plan with a health savings account. Under IRS rules, you cannot continue to contribute to an HSA if you are enrolled in Medicare (even Part A) or, after age 65, you are receiving Social Security retirement or disability benefits. You can draw on funds already in your account, but you cannot add to them. For details, see "Can I Have a Health Savings Account as Well as Medicare?"
You'll be able to sign up for Part A without risking a late penalty during the same special enrollment period when you enroll in Part B, after you finally stop working.
If you are married to somebody who has an HSA at work, and you are covered by that plan, it doesn't make any difference whether you are enrolled in Medicare or not — you can still use the HSA for your medical needs. The IRS rule applies only to the working employee who is contributing to the plan.
Will I need Part D prescription drug coverage?
Probably not. If your employer plan offers prescription drug coverage that is "creditable" — meaning that Medicare considers it at least of equal value to Part D coverage — you don't need to enroll in a Part D drug plan at age 65. Instead, when your employer coverage ceases, you'll be entitled to a two-month special enrollment period to sign up with a Part D plan without penalty. Your employer plan can tell you whether it's creditable or not. If it's not, you would need to enroll in Part D during your initial enrollment period at age 65 to avoid late penalties if and when you eventually signed up.
What if my employer offers me COBRA or retiree health benefits?
It's confusing, but different rules apply to Part B and Part D in either of these situations:
Part B: You can delay Part B enrollment without penalty only while you or your spouse is still actively working for the employer that provides your health insurance. But if you receive COBRA benefits — a temporary extension of your employer coverage that usually lasts 18 months — or retiree benefits, by definition you are no long working for this employer. So if you wait until these benefits have expired before enrolling in Part B, you won't qualify for a special enrollment period. Instead, you'd likely pay late penalties, and you would be able to enroll only during the general enrollment period that runs from Jan. 1 to March 31 each year, with coverage not beginning until the following July 1.
Part D: As long as your COBRA or retiree drug coverage is creditable, you do not need to enroll in Part D until these benefits end, as explained above.
Patricia Barry is a senior editor for AARP Integrated Media and the author of “Medicare For Dummies” (Wiley/AARP, October 2013)