A. Yes, if you are still working and are covered by your employer's group health plan, you can forgo Medicare without any consequence.
However, if you retire after age 65, you must enroll in Part B plan within 8 months after the month you retiree, even you find it may be cheaper or easier to continue with your employer's coverage - either through corporate retiree medical benefits or COBRA, because if not, you will face significant risks,
Consequences of Not Enroll in Part B After Age 65
If you miss this deadline and your employer coverage ends, you could find yourself uninsured for many months as you will not be allowed to enroll in Medicare Part B until the next general enrollment period which runs from January 1 to March 31. Your coverage won't start until July 1. Plus, you may be subject to lifetime late penalties - for each 12-month period you delay enrolling when you are eligible, you will pay a 10% of your Part B premium forever!
Initial Enrollment Period Trap
Even if you leave your job before you turn 65, the initial enrollment period rule could still apply to you. For example, if you leave job in January and turn age 65 in October. The initial enrollment period starts 3 months before the month of your 65th birthday and ends 3 months after your birthday month. Because your 65th birthday is in October, your initial enrollment period would have run until the end of January of the following year.
However, if you stick with COBRA for the full 18 months, it would expire in June the following year and you already missed the initial enrollment period, and the next enrollment period won't start until January the next year and coverage won't start until July the next year, you could end up without coverage for about a year, plus a lifetime late enrollment penalty!