Dear Liz: I am 65, still working and have health insurance through my employer. I have not enrolled for Medicare and have been told I do not need to. I plan to once I retire. There is a passage in my Social Security statement that says, “Because you are already 65 or older, you should contact Social Security to enroll in Medicare. You may be subject to a lifetime late enrollment penalty. Special rules may apply if you are covered by certain group health plans through work.” I have tried to research further through the Medicare website but can’t find a clear answer about whether or not I am OK not enrolling at this time.

Answer: If your employer has 20 or more employees, then you’re fine for now. When you stop working for that employer, you’ll have eight months to sign up for Medicare without owing penalties.

If you want your Medicare coverage to start when your job-based coverage ends, though, you should sign up a month before you retire. Similar rules would apply if you were covered by a spouse’s workplace health insurance plan. As long as your spouse is still working for the employer that provides the coverage, you can avoid permanent Medicare penalties.

If your employer has fewer than 20 employees, however, you may be required to sign up for Medicare when you’re first eligible. Check with your employer.