I do believe I am one of the few that does not use plugs...nor have I ever. I am 31 now, been playing for about 10 years in a band at stage volume. At first my ears would ring so I tried a set of the foam things, used em for a week in practice to try to get used to em for the stage. They worked well for me but made on stage communication reduced to crude hand gestures or the guitarist flagging the neck of his guitar up and down which never worked. I simply lowered my own level and improved my skill level in the same movement. Remember loud does not equal good, but hearing your mistakes allows improvement.
For the last few years up to today, I remove any speaker from around me, the amps point straight forward and are at least 6' away at all times, I use no monitor speaker, and I play at a level that I could nearly carry on a conversation behind the kit at all times. Since I lowered my level of play I have not experianced ear ringing or anything of the sorts. The guitarist and bassist both use ear plugs because everything is pointed directly at them...ie the amps and my drums. It gets really loud where they stand.
Having said all of that...am I damaging my ears? I am sure that at some level there is some damage being done. I am doing what I know works for me to reduce the damage done. I am sure they make some high tech ear protection devices that eliminate risk and I really hate to put a dollar sign on a sense, but I can't afford high dollar stuff. I could afford the foam specials or some $25 dollar ones like my bandmates use...and I may soon try em again cause I aint gettin younger!