Rolex make numerous watches, but their movements are rated to be 99.999 % accurate per day and to perform at such accuracy for 24/7 for years (five) between service intervals. A Rolex movement is a micro machine, no batteries, no manual winding required, it is made and assembled to comply with microscopic tolerances. Imagine being able to say the car of yours could run 24/7 for five years without a service yet still run as efficiently as day one.