When i bought my last bow i shot it for about a month, then i'm guessing the string finally got stretched out or something because i took it out one day to shoot and i was shooting way off. Well i'm going to buy a new bow tomorrow and i was wondering about how many shots it takes to get a string fully stretched out? And after that will i then have to sight it in again? Also i heard that if you are hunting in the rain and your string gets wet and you dont have wax on it the string will stretch out more...is this true? Thanks

When I bought my last bow (last year) we did the initial tuning at the shop and then I was told to take it home and put 200 shots on it and bring it back. A few days later I went back and we retuned the bow and they told me to take it back again after another 300 shots. I went back a week later and they did a checkup but no additional tuning was needed.

And from what I understand rain could definately cause your string to stretch if it's not waxed.

At the beginning, you are trying to remove the creep from a string, and the number of shots that takes will depend on the string. A custom pre-stretched string may be fully settled after a dozen shots, while a cheaper machine maded model might need hundreds of shots. The string material will affect the amount of stretch. Material like Ultracam has very little stretch, so once the creep is taken out, it remains very stable in length. On the other hand, a material like D75-thin, is a more stretchy string, and will tend to move a bit more, even if pre-stretched. It is also more affected by heat and humidity.

I just replaced my sting after 3 years of use. It strected 3/4 inch over the 3 years. Now, when did that happen your guess is good as mine. My groupings never changed and I never feel any change in my draw lenght & anchoring spot. I know over time the string will strech under any conditions

As said depends on the string material and the maker. I make my own so know when I make a 93" string it will be 93" next year when I change it. I have also seen strings that are stretched up to 3/4" but since I don't know the length when it was put on (some strings vary a lot from what is called for) I can't say how much was stretch and how much was just a poorly made string. Using 450+ I don't notice any change from initial making through sighting in and beyond. I also recommend changing a string every year as a string takes a lot of abuse, so why not be safe with it?
Moun Dave, where are you at? I'm in Erie. If you're near North East my friend has a shop (Dave's Archery), stop in and we can shoot the bull.