You don't have to turn the switch on the watch to keep it running.
Most self-winding watches have mechanisms to prevent overwinding.
A self-winding watch will have the rotor (a spinning weight) inside the caseback (the "lid" on the underside of the watch), which for some particular makes and models do not have a display caseback (a caseback with a window to show the rotor and the movement) makes it difficult to identify.
There's a relatively heavy part within each self winding watch, which responds to changes in gravity. This piece will always want to point down. As the watch is worn during the day, it winds itself.
It depends on your watch.
One type of watch is known as the "self-winding" or "automatic watch," which winds itself using the natural motion of the wearer. Movement rotates a winding rotor, which winds the watch via a ratchet. Other analog watches also bear self-moving parts, though for most this merely consists of the watch hands and associated gears.
The self-winding watch, also known as an automatic watch, was invented by John Harwood in the 1920s. Harwood patented the design for a watch that could wind itself using the natural motion of the wearer's arm.
The Bulova L9 self-winding watch was likely manufactured in 1959. The "L9" in the model name corresponds to the year of production, with "L" denoting the decade (1950s) and "9" representing the specific year within that decade.
Rolex
If the watch is relatively new or still within its warranty period then it may be returned to the manufacturer for repair. Otherwise, it could be taken to a specialist watch and jewellery repair workshop.
A Self-Winding Sidewinder - 1973 was released on: USA: 9 October 1973
Winding a watch is actually the process of storing kinetic energy. This energy is released as the watch winds down telling the time.
The Omega Seamaster Planet Ocean is a watch made by the Omega company. It is a self-winding watch with amazing features like being waterproof up to 2000 feet.