If you are planning to continuing to work until age 66 or beyond, you may not need to enroll into Medicare at all. It is going to be up to your company and the insurance company.
Some companies require that you enroll into Medicare Parts A & B and the company insurance will act as the primary, while Medicare acts as secondary. If this is the case, you need to keep in mind that if you have any health issues you may be limited as to which plan you can enroll into when you retire. What I mean by that is, you can enroll into a Supplement at any time, but if you are outside of your six month window for enrolling into Part B, you will have to pass underwriting to get into the better options. If you use your Guaranteed Issue provision you may not be getting the best coverage for you.
Some companies will require you to only enroll into Part A. This is one of the better options for you as it will allow you to defer your enrollment into Part B. Once you retire from your current job and enroll into Part B you will have all of the options available to you without having to answer any health questions as you will be in your Open Enrollment period.
Some companies will not require you to do anything, as they will continue to cover you as they always have in the past. If you fall into that category, then you can explore what it would be for Medicare to cover you, and compare the two policies. This will allow you to make the right decision for you.
If you have any questions about anything with regards to Medicare or any other Health Insurance items, please call me at 803-563-8534 or send me an email with you questions. I am not interested in selling you anything, I want to give you the information you need to insure you are covered to your satisfaction.
All the best,