Replacement time will vary depending on many factors. First off, you don't need to replace your string until it breaks. However, you many also need to replace your bow if you wait that long. Second, strings don't alway show wear before they break. This means you have to factor in all the variables to make an informed decision. Third, you don't want to try to time this perfectly. You're better off replacing too soon, rather than too late. Believe me, you don't want a bow string breaking while at full draw - trust me!

How soon a string will fail, depends on many factors. The amount of use is just one small one. Even more important is the material the string is made out of and how well it was constructed. Servings protect the string, so good servings can extend it's life. In addition, a well maintained string will last longer. Strings are damaged by water and friction, so frequent waxing is good to protect against those. Strings can be constructed in different ways. Some are better than others. A good custom string has the potential to be a much more durable product and one that doesn't creep much over it's life.

Life is full of choices and this holds true with string materials as well. You can go with a more durable material, but these tend to stretch more. Stretch is bad for holding the tune on a bow. Maintenance is much higher on these because you need to frequently add twists to the string. I make my own strings and I prefer Ultra Cam because it's the least stretchy material on the market. It contains the highest percentage of vectran (which doesn't stretch at all). The trade off is that vectran makes a string more brittle. These strings are more prone to breaking unexpectedly. On the other hand, one that is built properly, may not stretch even 1/16" in a year. This means your bow stays in tune longer and you hardly ever have to add twists.

Factor in that you can make a string built for speed (fewer strands, along with smaller and lighter servings) or one that is built for durability and less movement and you can see why there is a great range in string life. I shoot on average about 5-8,000 shots/year on my Ultra Cam strings and I've never had one fail. I've built them for many friends and have yet to see one break, but we all change them at least once a year.

I don't choose string mateial based on what will last longest. I choose what will work best for me. In my opinion, the string is second only to your arrows in importance to archery success. I constantly see people buying $700 bows and then neglecting the string. My philosophy is that any bow will work fine (and it will), but you should pay a lot of attention to choosing and maintaining the string, which can make or break your success.

I hang out quite a bit at the local bow shop and I can't remember the last time I saw someone come in to have their string checked out. 98% wouldn't have a clue if their string had crept 1/2" or how to check for creep. And most wouldn't consider replacing one unless they saw a broken strand or two. I have flat out never seen anyone come in and ask to have some twists added to their string to get it back to spec. Yet, many are constantly worrying about irrelevant things like arrow speed, or the cosmetics of their bow.