[ame=http://www.youtube.com/watch?v=_WTD9s5RNKY]YouTube - How Much Do You Really Use Your Apps? - iOS Vlog 348[/ame]
App Stat is an app from Cydia that will track the usage of your apps. It will tell you when you last opened them, how many times, and how long did they stay opened. These stats have many uses and could help you see which apps you need and where. Unfortunately it doesn't tell you stats previous to downloading.installing the app, but it's a good time to start. Anyways, App Stat is free in Cydia and a great thing to have on your device.