National Odometer Day is observed on May 12 each year, celebrating the invention of the odometer, a device that tracks vehicle mileage. This day encourages car owners to appreciate how odometers help maintain their vehicles by monitoring distances traveled, which is essential for scheduling maintenance and ensuring efficient fuel use. Typical customs include taking a drive to observe one's odometer readings, resetting it after each trip, and sharing travel photos that highlight the distances covered. The term "odometer" originates from Greek, and its historical roots trace back to Ancient Greece and the Han Dynasty in China, where early versions of the device were developed. National Odometer Day serves as a reminder for individuals to check their odometers regularly and care for their cars.