Primarily, if a watch stops frequently, gains time or goes through batteries very rapidly is a good sign the watch needs to be overhauled. Overhauling is the process in which an experienced watchmaker carefully disassembles a watch, inspects for wear, damage and dirt build-up. The movement (inner workings of the watch) is cleansed is a solution removing all contaminants that would cause the gears to slow or jam resulting in unreliable timekeeping. Afterwards, the workings are inspected and suspect trouble parts are replaced. The watch is then recalibrated, reassembled and tested thoroughly.