I have a friend who is in his early 60's and didn't wear any kind of hearing protection When he started shooting when he was a kid, and didn't start wearing anything until after he came back from Vietnam. Between the jet engines on the planes he worked near, and the shooting, he's very deaf at this point. He said he never really even heard of wearing anything while shooting until about 1969 or so.
For an almost 54 year old guy, I have remarkably good hearing, but it used to be amazingly good. I could hear watches ticking away in a quiet room, and I could hear many remote controls when buttons were pressed (I won quite a bit of money betting with people I could do it) from several feet away. Now, I have to have it right next to me to hear them, but I still can hear the whine that many of them make.
I somehow managed to keep my hearing pretty well intact, even though I shot a lot of big fireworks off when I was a kid, along with thousands of .22 blanks. Most of my damage came from a couple things, nitro Top Fuel and Funny Cars, and my old dog, who was basically all lungs, yapping his head off next to my left ear while driving. He barked or screeched at all kinds of stuff he saw, and it was very unpleasant. I started going to see the nitro cars in 1973, and ear protection was considered "wussy" or "girly" until around 1980 or so, when suddenly, even the crews for the cars started wearing some kind of protection. One of my friends went with me to a single race in 1977, and he swears his hearing hasn't been right since that day. I managed to make it through over 100 races with about 3000 passes made, without any serious damage.
Watch the camera guy jump when the throttle is whacked:
http://www.youtube.com/watch?v=XR7aF4hY9rU
The ear doctor said I have the best hearing of any male patient of his over 45, and my hearing must have been incredible for me to be able to say it's not good at all compared to what it was when I was 18 or so.