David got a Google Nexus 5 phone and he's concerned about battery life. Leo says that's the main problem with modern mobile phones -- they don't last through the day, which is why he likes phones that have removable batteries. What about killing programs and tasks that are running? Leo says that today's modern phone operating systems don't require task management anymore.
David will want to avoid wake locking, where the phone can autoupdate itself or get email and notifications. This wakes up the phone and wears down the battery. He should turn off push data, and change his app updates to manual. Programs such as System Panel and GSam pinpoint battery drains so he'll know what's draining his battery.