What is the fine-grained topic of the following text: My mother also haves a same phone, she hadnt really used it ,hasnt installed any apps, and her phone can last for days in offscreen without charging..
StopAd, AvastAntivirus, GoogleMaps, GoogleEarth, Skype, "Mechanical Engineering", some games.., voice recorder, wifi analyzer, Picai, 9gag.. Only return the topic.
Phone battery life and usage