Walking reserve: what it means and why it matters

You take off your watch on Friday evening and put it back on Monday morning: it has stopped. The culprit is its power reserve.

Definition

The power reserve is the duration during which a mechanical watch continues to run once fully wound, without being worn or wound again. It depends on the mainspring, which stores energy, and the movement's power consumption.

How long is it generally?

On many classic automatic watches, the reserve is around 38 to 50 hours. Some recent calibers exceed 70 hours, and a few exceptional pieces last several days. The exact value is stated in your watch's manual.

Why does a watch stop before its stated power reserve

The stated power reserve corresponds to a fully wound watch. If you wear it for a short time or with little movement, at the office for example, the rotor only recharges part of the mainspring. The watch then stops earlier than expected.

The solutions

• Hand-wind it: on most automatic watches, a few dozen turns of the crown restart the mainspring. Stop as soon as you feel resistance and never force it.
• Use a watch winder: it continuously maintains the power reserve, effortlessly. It is the ideal solution if you alternate between several watches. Discover our watch winders.

And the power reserve indicator?

Some watches display the remaining power reserve on the dial, in the form of a small graduated arc. It is a practical complication to know when to wind your watch, or when to place it on its winder.

Properly setting your winder allows you to keep the power reserve full without straining the watch: consult our TPD setting guide by brand.