I can see on every guitar I've made, though, a little improvement in that area, I learned how to sharpen the bit before every job, how to rout a little bit at a time so you don't bite chunks off the soundboard, how to improve on the precision of the rout with a square file and a square stick with sandpaper, how to aply pressure on the bindings during the glueing with inner tube bands. Nowadays the job comes out perfect.