Extending Battery Life
Most Fitbit devices have a battery life of five to seven days, but you can extend that with a few tricks. In general, anything that makes use of the Fitbit's screen will deplete the battery, and that includes alarms and notifications. Setting fewer alarms or disabling some of your alarms can help your Fitbit's battery last longer.
You can also disable notifications. Your Fitbit's screen won't show you who's calling when your smartphone starts ringing, and it won't vibrate, so it will use less power.