I think most competitive shooters have an idea of what they can get away with. I know that my M2 starts to hiccup around 500 rounds. So, I know that if I shot a big match and have a couple of practice session under my belt that I better clean before a match. I clean my 625 when it looks so disgusting that I can't stand the way it looks anymore. I haven't seen a round count where it fails. I've put 2k rounds through it between cleanings. My AR always runs, but I do not clean it before a match. I clean it, go to the range to verify zeroes and go to the match. I've heard too many stories from high power shooters about clean bores shooting a little off. I said all that to say that you have to know your gun.