since the movement on your wrist is the source of the energy to power the watch, by spinning the rotor, if you leave it untouched for a few days it will eventually stop.
The latest ones go into sleep mode if not worn for a while. The internal computer keeps running but the hands stop moving - thus conserving the major portion of the power. Pick the watch up and give it a shake, and the hands will resynchronise with the counter and show the correct time. The Kinetic Relay watch can continue to function even if left resting for up to 4 years - somewhat more than "a few days"!