Do you have to register with the Social Security Administration three months before your 65th birthday? Tom Margenau answers this question and more in his column, Social Security and You:

Q: I will be 65 in February 2012. I’m still working and plan to keep working until I’m 70. A friend told me that I have to register with the Social Security Administration three months before my 65th birthday even though I don’t plan to take my Social Security yet. Is this true?

A: There really is no such thing as “registering” with Social Security — at any age. You simply file for your retirement benefits a couple of months before you want them to begin. And in your case, it sounds like that’ll be about five years down the road.

I think what your friend was trying to tell you is that you probably will want to sign up for Part A Medicare to start at age 65. And you would do that through your Social Security office about three months before your 65th birthday.

There are two main parts of Medicare. Part A is hospital coverage, and it’s free. Or rather, you paid for it — and continue to pay for it — with your payroll taxes. (If you look at your pay stub, you’ll see a deduction box labeled “Medicare Tax.” That’s buying you the Part A hospital coverage of Medicare.) Even though you likely are covered by your employer’s insurance, you might as well take Part A, just because you’ve already bought it. And there may be times when you need it. Also, there’s a chance that your employer’s insurance might require you to take Part A.

The other main part of Medicare is Part B, or medical insurance. Part B essentially provides partial coverage of all health care costs not associated with inpatient hospital bills taken care of by Part A. Medical insurance usually costs about $100 per month. (It’s not paid for by your Medicare tax deductions.) However, you do not need to take it while you’re still working and covered by your employer’s insurance.

So you should sign up for Part A now. And then you should sign up for Social Security benefits and Part B Medicare coverage when you retire.