Only an expert watchmaker should be trusted to put your watch back into working condition. It's best to replace a battery in a quartz watch before it runs out. Dead batteries left in the watch can leak or corrode and ruin it. Also, don't attempt to change the battery in a watch yourself. Take it to a jeweler.
Batteries run for about two years.
Those in some less expensive, multi-function digital have shorter lives, as little as six months, if the wearer frequently uses extra features such as a calculator or game. Finally, if you have any questions, ask your jeweler.