The app only uses up to 10% of your available network. You won't feel a difference in performance on your computer, phone or internet speed. You can always turn the app off and it will not run anymore in the background and use any bandwidth or battery life. Speaking of battery life the app does not consume any remarkable more battery life but when leaving the home you should turn the app off nevertheless. Mobile bandwidth of your phone is only used if you allow it in the app settings, by default the app only uses bandwidth in the background when you are connected with a Wifi network.