After going through range exercises today, I once again could not surpass my limit that hasn't expanded in the last 4-5 months. I don't know what it is typically for people, but prior I could add half a step every 3 months or so, or at least make my top notes musical and stronger. I'm not asking how to improve my range though (I've discussed with my teacher), I'm curious if there is a set limit to how high we can play. Whether that's individual physical characteristics that determine it or not etc. Besides that it seems that most of the best screamers top out at a triple X note but why not quadruple?