How careful do i need to be while rideing? Potholes? rocks? curbs r a no no? They look so fragile and i have never droped this kinda money on a bike so i want to at least have an idea of what is exceptable. I am somewhat ruff on my toys. Also what is a good rule of thumb for saddle height. The guy at the shop said level with the handle bar was good for me, but i allways see them raised on other set ups. maybe cause im only five nine and a half?