Quartz watches work with energy supplied by a battery. Quartz watches have no balance, and the timekeeping element consists of a crystal of quartz. Whatever the watch's position, its accuracy will always be identical.
Watches equipped with a mechanical movement receive their energy from a wound-up spring. If your mechanical watch has manual winding, you need to turn the crown to wind up the spring. Automatic (self-winding) mechanical watches also use the spring system, but the winding of the spring is carried out by the movements of your wrist, which cause an oscillation that supplies the energy required for the winding system.
If you are not particularly active or do not often wear your watch, the mechanism of your watch may not be wound up enough for it to work properly. Whether it is mechanical or automatic, your watch may be slightly fast or slow, depending on how you wear it.
If your watch is regularly fast or slow, a Cartier master watchmaker can carry out small adjustments to restore it to good working order. Please note that the mechanism of your watch may need a Complete Service to restore its original accuracy.