Welcome to the forums EMMY4571! I am thrilled that you love the Samsung Replenish! It rocks a 1600 mAh battery which provides up to 5.4 hours of continuous talk time. If you are having issues with battery life maybe you can try some of these tips:
Check for available software updates: Menu > Settings > About phone > System updates > Update Android.
Change the settings for the backlight brightness and backlight timeout to the minimum setting acceptable: Menu> Settings > Display > Brightness/Screen Timeout.
Change live/animated wallpaper to static wallpaper if applicable. Menu > Wallpaper
Turn off network connections such as Bluetooth, Wi-Fi, or 4G when not using them: Menu > Settings > Wireless and network
Turn off GPS when not using: Menu > Settings > Location > Uncheck Use GPS satellites
Limit the number of applications running at the same time and close applications not being used: Menu > Settings > Applications > Running services > choose the application and click stop.
Set the device to auto sync e-mail and applications less frequently: Menu > Settings > Accounts and sync > Uncheck Auto-sync or choose specific applications and adjust sync timing interval. Can also choose any applications not being used and uncheck sync boxes.
Do not use the vibrate setting as a standard notification setting: Menu > Settings > Sound > Vibrate
Charge the device on a regular basis such as nightly to maximize battery life.
If none of these steps help resolve the issue - please get the phone into your local Sprint Service & Repair Center. Please let us know what you find out!
Sprint S.M.A.R.T Agents Sprint S.M.A.R.T Agent are here to help Monday through Friday 6:00 AM CT - 6:00 PM CT. If you need to speak to an agent outside of these hours, please visit Sprint Chat