Instructions
Check that the watch is fully wound by rotating the dial on the side of the watch clockwise using your fingers. Most wind-up watches need to be wound every day, some last a little longer. However, wind-up watches start to lose time before they actually stop, because the tension in the small spring is not enough to maintain accurate time.
Compare the time from your wind-up watch to another accurate timing device, such as the time display on your computer or cell phone. These usually use the Internet connection or radio waves to maintain time accurately. If you find your watch is losing or gaining time compared to the other device over a period of time, and the watch is fully wound, then it needs servicing.
Wind the dial on the side of the watch using your fingers. It gets slightly harder to wind when it's nearly fully wound. However, if the tension doesn't increase and you can carry on winding continuously, then it's likely the spring has snapped, and you need to get it repaired.
Pull out the winding dial on the side of the watch using your fingers. This releases it from the winding mechanism and allows you to change the time. If your watch keeps stopping at the same time each 12 hours, then move the hands and reset it. Push the dial back in and then wait to see if it stops again. If it does, then the two hands are touching each other when they meet. This makes the watch stop because the hands are out of alignment. You need to get the hands realigned.