You should never listen to music at high volume on headphones or earphones, you WILL damage your hearing over time (or sometimes in one sitting, both happened to me).

You can tell young people this until the cows come home but they'll ignore you and assume it won't happen to them...

and then once the damage accumulates and they're a little older with annoying tinnitus forever or more painful ear damage (like myself) they might finally start giving this advice out to younger people who still have a chance at a healthy, ear damage free life. But by then it's too late for themselves, and the younger people won't listen :-(

There are awesome earplugs you can get that you should wear if you're somewhere loud like a nightclub or a concert by the way. They start very cheap, and they're designed to "turn down the volume" of the world without affecting how it actually sounds.

(They're not electronic or anything, they're just cleverly made)

You can get more expensive ones that claim to be even better at this, but I find the cheap ones to be fantastic. I carry them with me all the time now, and if I end up somewhere loud, in they go. Heck, I even use them when I vacuum - those machines are loud as hell.

Oh and similarly, wear earplugs when you're using noisy powertools - table saw, grinder, etc.