A method of monitoring the wear of drill bits for drilling wells in earth formations, several embodiments of an improved drill bit for drilling a well in an earth formation, and methods of manufacture. In one embodiment, the bit is assembled by forming the bit, including a bit body and a plurality of cutting components; introducing a wear detector into the bit; and providing a module to monitor the wear detector and generate an indication of bit wear. The wear detector may be a witness material that may change a characteristic of at least a portion of the bit. The module may detect when the witness material is separated from the bit. The wear detector may be introduced during or after formation of the bit. The bit wear may be displayed for an operator.