It is recommended that every 5 years, a watch undergoes an overhaul: a complete disassembly of the watch, re-oiling of the parts and adjustment to make sure the watch will keep the correct time. Mechanical watches, which include automatic and manual wind watches, have several moving parts. In order to function properly, every moving part is oiled to ensure that friction does not cause the parts to wear away. This oil eventually dries up and the moving parts of the watch can start to incur damage.