RE: Important question re: bowstring
A lot of abuse is under the serving where the nock goes that you can't get at good or see. We used to get guys coming in a week or two before season with strings broke here. The strings were usually 5-6 years old and just snapped. This is in addition to the already mentioned stretching, etc. Your string takes a lot of abuse so I would recommend every year for the string and the cable every two years if you don't do them both at the same time.