I've had tinnitus for more years than I care to remember, probably caused by loud gigs, clubbing and jamming too loudly in acoustically dreadful rooms (like garages).
My tinnitus isn't that annoying to be honest, it's bearable and only really noticeable when it's quiet. I did however go and get my hearing in general tested a while back and, apart from the audiologist telling me my hearing starts to fall away at about 8khz, he went through tinnitus. Apparently it's an audio hallucination, in that what you're hearing isn't actually there. He also said that in some cases you can get something similar to a hearing aid that cancels out the hallucination...or something like that, it was a few years ago now. As someone else posted, I get that thing where I struggle to pick out what people are saying if I'm in a crowded room with lots of noise (not noisy, just lots of noise). My hearing tends to get saturated by background noise and will struggle with what the person speaking to me, who maybe only 3 feet from me, is saying.
I've been quite fortunate in the last couple of bands I was in in that they were not loud, at all. One was helped in that there was no drummer, and the last one the drummer rarely used anything other than brushes as he said "any louder would annoy me more than you guys". It was a struggle to get him to use hot rods to be honest. On top of that the guitarist/band leader just won't put up with loud playing, a drummer who can't control their volume isn't a very good drummer in his opinion. I tend to agree.
Now, I simply refuse to be in a loud band, or go and listen to a loud band, and I still have my earplugs with me for practices and gigs.
I went to watch The Dammed with a work mate a few years ago, it was stupid loud. Luckily I remembered my earplugs, so unlike my work mate I didn't have a ringing in my ears like a jet plane taking off. Amps, cabs, PA's and whatever may be able to go to stupid volumes without packing up, distorting and the like, but your ears can't. The gear will be pumping out excellent quality sound, but your ears will start crapping out, so you can't hear the music etc properly, it's just dumb. Just turn it down a bit and you can hear the instruments, the vocalist etc.