Before I put a finish on a new bow I leave the bow braced for several hours at a time, pull it to full draw on a tree about 1000 times and shoot about 100 arrows through it - I do this over the course of a week. If it doesn't develop frets, lift a splinter or change tiller, I consider it good to go. If a bow is going to develop a problem this regime will generally catch it. But I've had a couple fail even after passing this test. Unfortunately you just can't be certain with wood.