I didn't see anyone mention using plain wood filler for filling in routed spaces on the body. I've used this but noticed after a period of time, the filler shrinkgs and has to be touched up. Other than this set-back, what other problems can be expected from using wood filler over a period of time? Is it possible it may lose it bond and 'fall' out of the guitar?
What I'm speaking of, of course, is filling in large holes like the input jack hole (think of the large hole a strat uses for it jack plate) or the pickup routing or the back where the springs may have been (although, I would probably use wood blanks back there and touch up with some filler :S)