I stock 3 types of tech screw and one type of wood screw in 3 sizes.
Pardon the pun, but a good screw greatly reduces the amount of bits you will go through for general sign installs mainly because the screw self taps itself into the surface.
secondly, as you have just said yourself, "quality" of the bit is very important, but more so the person doing the drilling.
i used to go through tons at our place warren, the bit quality and the person drilling is the main reason. bit sharpening, had one years ago and i never used it. as quick as we had the blade sharp again, it was blunt again. 😆