digital camera watch from the early 2000's : 6 months of battery life on a CR2032 coin battery. Current day smart watch (without a camera in most cases) : 24 h

digital camera watch from the early 2000's : 6 months of battery life on a CR2032 coin battery. Current day smart watch (without a camera in most cases) : 24 hours to 1 week battery life using a lithium ion battery.