If for some reason your Android powered smartphone does not perform as good as it used to, or you want to sell it I suggest you to bring it to its original factory state.
If you are on a certain data plan on your mobile provider, and don't want to exceed it, you can set data usage warning and a limit which can help you save some of your money.
Samsung Android devices such as Galaxy S2 or S3 come with a cool app called Kies Air, enabling you to connect via WiFi connection and manage them using a web browser.
Nexus 4 smartphone comes with a bunch of Android widgets you can add to one of the screens. Let me show you how to add a widget to a screen and how to customize it.