Power Reserve Watches

The power reserve indicator is one of the most useful features of a mechanical watch besides the actual time display. A mechanical watch is operated either by automatic or manual winding. In order to run at a regular rate a mechanical timepiece needs to have at least 30 per cent of its mainspring wound. An automatic timepiece needs to be worn for about 10–15 hours before it is fully wound. The power reserve indicator displayed on the watch with automatic winding movement shows how long a watch will function when not worn. On a manual winding watch, it shows the time left until the watch needs winding.