Whether it's to your advantage to enroll in Medicare Part B medical insurance or in a Medicare Part Dprescription drug plan while you're still working full-time depends on the extent, cost, and rules of the health insurance coverage provided through your employment. With regard to Medicare Part A hospital insurance, most people have no premium to pay, so there is no reason not to enroll when you turn 65.
For Medicare Part B, you have to consider Medicare's rule regarding late enrollment. If you do not sign up for Medicare Part B when you first become eligible for it at age 65, you may have to pay a penalty of 10% per year in the cost of your monthly premiums for each year you have delayed enrolling, if and when you do finally enroll in Part B. However, this rule does NOT apply to people who are enrolled in a health insurance plan through their current employment. So, if you've got a health insurance plan through your current employment, you don't have to worry about a penalty for delayed enrollment.
The next thing to consider when deciding whether to sign up for Medicare Part B is the rules of your employment-based health insurance plan. Some plans require employees to enroll in Medicare Part B when they turn 65. Check with your benefits administrator at work to find out what the rules are regarding Medicare Part B sign-up under your employer-sponsored health plan.
Finally, you have to determine if it makes financial sense for you to enroll in Medicare Part B even though you've already got health insurance through your employer. If you have both Medicare Part B and a private health plan through your current employment, the health plan pays first if your employer has 20 or more employees, with Medicare picking up some copayments the private insurance plan doesn't pay. If your employer has fewer than 20 employees, then Medicare Part B would pay your medical bills first, with your employer-based insurance picking up most of what Medicare doesn't pay. The monthly premium for most people for Medicare Part B is $96.40 per month. So, you need to figure out whether you regularly have more than $96.40 per month in medical bills that your employer-based insurance doesn't cover. If you do, then signing up for Medicare Part B would be a good idea.
You should go through the same process with regard to deciding whether to sign up for a Medicare Part D prescription drug plan. Medicare Part D plans cost anywhere from a few dollars a month up to $100 per month, with the average coming in at around $25. If your current employer-based insurance doesn't cover prescription drugs at all, then enrolling in a Medicare Part D plan probably makes good sense if you have regular prescription drug costs of more than $25 per month. If your current insurance plan does cover drugs, signing up also for a Medicare Part D plan probably makes sense only if your current insurance still leaves you with more than $25 a month in unpaid drug copayments or other costs.
Editor's Note: The coverage described above may have changed. For the most recent information, please check Medicare.gov's eligibility tool[medicare.gov].