RNID (The Royal National Institute for the Deaf), has recently promoted a Deaf Awareness Week.
People need to be more aware of the damage that too much noise can do to your ears, says the RNID. A few hours of ghetto-blasting volume, over-loud iPod listening or sole-vibrating sound at an eagerly anticipated gig could do damage to your inner ear that you'll only find out about years down the line. Same goes (unfortunately) for prolonged instrumental practising.
You can do a DIY hearing test online from the RNID website. (Hearing test link.)
Having a hearing impairment doesn't always mean you're completely deaf. However, hearing problems can creep up on you. Can't hear other people in the cafe-bar? Always asking people to repeat themselves? Guessing what someone might have actually said? Makes you think. (Though being able to turn down the sound on a noisy train is a distinct advantage! I know.)
And if your own hearing is fine - maybe you might consider supporting the good work RNID does for those less fortunate.