Whilst most devices will easily last a full game, we strongly recommend that you fully charge your phone before you go out to play. Reduce the screen brightness to save on power too. If your battery is getting low then the app will warn you and if needed you can swap to another device by using the rejoin game pin. To do this simply load the game on another device, tap the grey cog on the top right-hand corner of the selfie screen and type in your team re-join pin. Enter the game and it will pick up where you left off on the new device - the old device will then be deactivated.