If you are buying an automatic watch please read these:

Automatic Self-Wind watches use a semi-circular weighted rotor to generate motion. The normal movements from your arm and wrist cause the rotor to move back and forth which automatically winds the watch. Manual wind watches are similar to automatics watches, however, some may not have an automatic rotor and therefore need to be hand-wound more regularly.

1. For a self-winding watch to function properly, the mainspring must build up a sufficient power reserve. This is called the initiation process. Without the initiation process, the watch may not operate properly or consistently.

2. To initiate the power reserve, the watch must be wound manually. Turn the winding crown, in a clockwise direction for about 8 to 12 revolutions. Ensure that the crown is not pulled out when you are winding the crown. (Winding the crown of the watch should not move the hands of the watch).

3.A self-winding watch should be worn several hours a day to build up the power reserve. If you find that the watch has stopped moving. simply restart the initiation process.