to answer your question a string stop does many things quiets the bow string with out slowing it down (granted its only a few fps but hay) keeps the string from hitting bulky sleeves from hunting coats, some say it gives the arrow a more consistent release from the string because the string stops at brace the same all the time. having one out weighs not having one. if your bow is 10 yeas old then I would get a new one. I did ,shot my 2004 hoyt till spring and bought a 2014 hoyt and wow night and day, but if your bow is a few yrs old maybe shoot a few new ones but keep a open mind on if they really are better.