I have been playing in Metal bands for almost 20 years. All things considered, I think I am doing pretty well. Yes I do get some ringing occasionally, but my hearing is pretty intact. I think I was around 28, and I was playing in 3 bands and recording other bands a lot, and I decided that I really had to start wearing earplugs.
The thing I didn't realize at first was, once you get used to wearing earplugs, it's not a big deal. But at first it is such a drastic change that it is kind of discouraging. Now, I carry earplugs with me all the time, and use them to sleep through noise, tune out the background on road trips, they are a really handy thing to always have in your bag.