Hearing loss is at epidemic proportions for today's musicians.. as everything is amped and electrified. The big things to help are:
1. Always have a brickwall limiter on your master when you are sound designing, and composing! Do not forget this.
2. Extreme high's and low's cause more damage than mid frequencies. Near-field monitors are supposed to be close, but you should not need to have there volume anywhere near mid level... Low, low volume is best. Turning up to check a mix, or check a certain frequency is probably ok.
3. Genetics are going to determine just how prone you may be to hearing loss. Although certain loudness will kill anyone's hearing.
4. Advances have been, and are continually being made in the fight against NIHL, and a cure may appear within 15 to twenty years.
5. Get your hearing checked regularly.. I know several musicians, "my age, younger and older," they can not hear a bloody thing. And many of them did not play in loud rock bands like myself for years, and years... What's the difference? I wore ear gear when we played out.. except for the odd practice, or when I was rocking out at home to my marshall... I wore ear gear at practices and home as well.
I notice producing.. No ear gear needed. Even my very inexpensive Alesis Monitors are so quiet and clear.. They only get loud if I go ahead and turn them way up..
Anyways.. One of the best mix engineer's I ever met.. He can not hear a thing. Its going to be one loud session in his studio whenever you are there, trust me on that.. you can't even speak up to him, cause he will not hear you... he turns the volume up like a live rock concert.. and his mixes? Banging.. He was doing major label stuff when I met him, I expect its the case now too.. unless he's retired. (also wouldn't surprise me) but shucks.. if he could mix deaf back then, why not now?
:p go figure