Horology glossaryDefined term / power-reserve
Power Reserve
The length of time a fully wound watch will continue running before it needs winding or wearing again.
Authentication note
Why this detail matters.
A caliber's power reserve is a documented, testable specification, so a movement that runs dramatically shorter or longer than the reference's stated power reserve may not be the caliber it's claimed to be. Testing power reserve is a straightforward, non-invasive functional check during authentication.