When there is a large amount of rest time, or when the watches are put away for a period of time, the energy lost should be replaced safely by automatic watch winders to prevent their becoming overstressed. Each watch needs a different pattern and frequency of motion to remain safely and completely wound. The manufacturer usually specifies the type of automatic winding that works best for that watch.
If a watch is worn regularly, a winding period once every two weeks is sufficient to keep the watch adequately powered. If a watch is worn only occasionally it will lose all its power. In order to have that watch running smoothly and ready to wear when desired, it should be set on a winder when it is stored away. If a watch will be stored most of the time it should be set on a winder that has scheduling controls.
Automatic watch winders with scheduling controls work on a desired schedule of rotations and rest periods. This is best to avoid constant motions that will eventually wear down the movement’s gears. Also, it is not necessary to keep an automatic watch at full power.
Motions that can be imparted to the watch are clockwise turns, counter-clockwise turns, and bi-directional alternating turns, where the turntable turns one way and then the other way automatically. The scheduling can be flexible. This is known as adjustable turns per day (TPD). One typical program may rotate in one direction for one minute and then rotate in the other direction for another minute. This pattern of rotations would continue for one hour at which point the winding turntable would rest for three hours. Low end watch winders will then repeat this pattern. High end watch winders can be programmed with varying patterns to simulate the varying conditions the watch will encounter when it is being worn. It is important to read the manufacturer’s instructions as to the best rotation pattern and rest schedule for your watch.
Some automatic watch winders are only battery-powered while others come with a power adapter. Many come with both. Battery power is important if you are away from a source of power, as on a camping trip, or on a long airplane flight.