Okay, I've been having this problem for a while now, with every instrument I've had. I set the String saddles to the height I like, and eventually, withing a week or two, they've fallen down. It really sucks on my bass, though, as it happens more drastically, more often, and I don't have the proper allen wrench on hand, it disappeared. Does anyone know why this might be happening? I play an indonesian-made Fender Squier.