Most retiree plans (i.e., coverage offered to former employees and their spouses) will inform you that you have to take Part B in order to be covered by the plan. If you don’t sign up for Part B when you first qualify for it, your retiree plan might pay little or nothing toward your health care.
Additionally, many employers offer retiree benefits through Employer Group Waiver Plans (EGWPs) – a type of Medicare Advantage plan. You have to be enrolled in Medicare Parts A and B to receive retiree benefits through an EGWP.