Snapdragon BatteryGuru is an app designed, obviously, for Qualcomm’s line of SoCs, promising extended battery life by learning your behaviour and adjusting the frequency that certain apps make network calls or run in the background.
The app itself runs behind the scenes, learning how you use your phone and, after a few days, gives you a summary of the changes it has made. It takes the apps you use the least and alters their background processes, ostensibly saving battery life in the process. You can, of course, overwrite the app’s choices — it changed Gmail to only check for email every once in a while — but I mainly left them at default to see how it impacted uptime.
It also learns where you most frequently connect to WiFi and turns off that connection if you’re outside that particular location.
It works on Snapdragon-powered devices running Android 4.0 or above, so give it a try on your Galaxy S III or Nexus 4.