RE: serving wear
Serving is a thin piece of string that is wrapped around your bowstring. If you look at where your nock point is you will see that this middle portion of the string has been served. It is also used above and below your peep sight in order to keep it in place. As far as serving wear, that is when the serving begins to wear through and come undone. This is usually caused by repeated shooting with a release and is most noticable right below the nock. I hope this clarifies matters for you, it's the best explanation I could come up with.