Probably YOU, or the tune on your bow. Did it suddenly happen, or had you not shot in a while and then when you got the bow out, you notice it's not hitting where it used to???? If you have to move the sight a LOT, then I'd check the peep, and make sure the arrow rest is "where it's supposed to be." I've had set-ups that as the string stretched, I had to continuously make slight adjustments until I got to the point that I had to "FLIP the base to allow the whole housing to be in a different position all-together. How old is the bow, the string, etc???