I bought a Martin Firecat from a buddy of mine about 8 years ago. I had the bow restrung and hunted with it for about 2 years.I shot the bow maybe a couple hundred times. I quit hunting and stored it in a case in the garage.I recently decided to start bow hunting again. I noticed the string was a little fuzzy but I do not see any frays. I want to know what the recommended time frame for replacement?