If you are 65 or over, eligible for Medicare, and have insurance through your or your spouse’s current job, in most cases you should at least take Part A (hospital insurance). For most people, Part A is free.

To decide whether to take Part B (medical insurance), for which everyone pays a monthly premium, you should ask your benefits manager or human resources department how your employer insurance works with Medicare and confirm this information with the Social Security Administration (SSA) and Medicare. Be aware that when you qualify for Medicare, your employer insurance may start to work differently for you. You will need to figure out whether paying for both types of coverage will be useful in offsetting your health care costs.

As a first step, assess whether your employer insurance will be primary or secondary to Medicare.

  • Secondary insurers generally pay all or some of the unpaid portion of covered health care expenses only after the primary insurer has paid. For example, after Original Medicare pays, secondary insurance could pay for the remaining 20% of the cost of a doctor visit. Without primary insurance, in many cases insurance that is supposed to be secondary will cover very little or nothing at all. If your employer insurance will be secondary, you should generally take Medicare Parts A and B when you are first eligible.
  • Primary insurers pay first. Generally, you do not need Medicare Part B if you have employer coverage that is primary, unless you are unhappy with that coverage. However, you may still want to consider whether paying for both types of coverage would offset your health care costs, or whether it would be cheaper to have one or the other.

In either case, you qualify for a Special Enrollment Period to enroll in Medicare without penalty after you initially qualify. You can enroll in Medicare without penalty at any time while you have group health coverage and for eight months after you lose your group health coverage or you (or your spouse) stop working, whichever comes first.

In some cases if you have health coverage from your union or current or former employer when you become eligible for Medicare, your coverage may automatically convert into a Medicare Advantage Plan (private health plan).

You have the choice to stay with this plan, choose Original Medicare, or switch to another Medicare Advantage Plan. Be aware that if you switch to Original Medicare or another Medicare Advantage Plan instead, the employer or union could terminate or reduce your health benefits, the health benefits of your dependents, and any other benefits you get from your company. Talk to your plan before switching to find out how your health benefits and other benefits will be affected.