For me over the years, it is comfort. Why. Because I have never really had anyone of skill set up my bow other than string my bow. I am not really good at everything and I know my bow is not even closely to perfectly tuned, so I shoot my bow so much that the small things(bad tunings) "disappear" in a sense...this year I need to chage it up and head to the pro shop so that someone can assess my form and tune my bow to fit me perfectly. I have gone too many years just relying on my practice time to overcome my shooting form/tuning flaws.