^^Ive changed 2 front wheel bearing on my e36 in the last year n a half.

A humming noise to one person could be a screeching noise to another person though!:wink:

Easy way to tell is jack up the car and spin each wheel. If the bearing is gone/going youll hear a rough noise when the wheel is spinning. Bit harder to do on the back wheels with drives attached though. If theyre really bad, the wheel should rock if you grab it and try to shake it in and out.