you don't need to sign up for medicare if you have employer-based health insurance. but your employer coverage must be from a company with more than 20 employees. the key is that the insurance be considered "creditable" or generally about as good as medicare coverage (ask your employer for confirmation that your plan qualifies). when you do sign up for medicare -- whether you draw on social security or not -- you will receive medicare part a at no cost and you'll pay a monthly premium for part b. if you need drug coverage there will also be a monthly cost for part d. once you lose your work-based coverage you need to sign up for medicare fairly quickly to avoid penalties.
why do you have to sign up for medicare if you already have good insurance and are still working? . is it the insurance company or medicare enforcing this? if you don't are you penalized and if you're not drawing social security do you still have to pay for it when you sign up?