Richmos, I listen to rock at 95 dB as measured (not guessing) all the time. That is a comfortably loud level and safe as long as you warm your ears up to it. With warmed up ears I will occasionally go louder. When I watch the Nine Inch Nails videos I'll push it to 100-105. If one can't listen at 95 dB comfortably it is most likely because something is distorting. Above 100 will disturb some people regardless of limited distortion like my wife.
n80 there are only basic rules. Like any other human trait there is a large range of sensitivity to sound and ear durability. It is not just volume but also the type of sound. Impulse noise like a gun shot is more likely to damage hearing than a steady noise at the same volume. In terms of music, if you warm your ears up 95 dB will never cause damage unless you have really bad ears. Some people will go deaf even living in a monastery. Everybody's ears will accommodate to volume given a brief warm up. As the volume increases the smallest striated muscle in your body, the stapedius tightens down on the stapes, the smallest bone in your body, dampening the volume your inner ear is exposed to. Some people think that people who repetitively listen to loud music develop a stronger stapedius with a better damping effect so they can tolerate loud volumes better without damage. These studies have never been done because they would be very expensive and nobodies interested enough.
I have been to plenty of loud concerts and have had systems capable of at least 90 dB all of my adult life. As a teenager I could easily hear 20 kHz. I tested my hearing just last month and could just make out 18 kHz which is better than most 65 year old. Now that is anecdotal and everyone can not expect to do that. There is no accounting for luck. But, just because you like loud music does not mean you are surely destroying your ears. You can download test tones and check your own hearing. Plug one ear and run up the tones then plug the other ear and do it again. Our high frequency hearing always declines with age. I do not know the data for sure but I think most 65 year olds can't hear much above 12 kHz
