in my personal experience,nothing,i have owned over 2 hundred bows in my life,most of the highend ones,and a lot of realy good one's,and i make my own also,some i even tiller,some have some positive tiller,and i can never tell any difference,i shoot 3 under.but now after only shooting 2 hundred bows or more some people with more experience than me will have more expert opinion's than my 2 cent's worth.let me add that all the bows i have owned were all kept for some time,some only a week some 2 or three weeks,some longer than that,but they were all shot plenty.best regards,robert