Wayne,
The wax is to help the string. The serving is there to protect the string when it rolls on the cams, on the idler wheel, and where you hook your release and arrow. Putting wax on these places causes the cams, idler wheel, serving areas to gum up and then you have a place that catches all kinds of dust, etc. The wax can also cause problems if it gets in the cams and clumps up. You could possibly have some malfunctions. I usually just put the wax on the string as often as possible, because as long as you keep the wax rubbed in and you don't use too much you aren't going to cause any problems. Thanks,
Trey