when do you need to apply for medicare part b
However, there is an exception. Whether you should enroll in Part B while you are still working depends on whether your employer has more than 20 employees. If your employer has more than 20 employees, you do not need to sign up for Part B right away because your employer's group health plan will be the primary insurer. When you retire, you will have a special enrollment period of eight months to sign up for Part B, without penalty. If your employer has fewer than 20 employees, however, you should enroll in Medicare Part B when you are first eligible.