This topic should IMHO be re-titled. Clearing apps out of the app drawer is not a waste of time. There are lots of apps which do in fact create enough activity in the background to affect battery life. Skype and Facebook are but two examples. VoIP, chat and messaging apps in general tend to want to run in the background to keep their socket connections back to the server open. Yes, in theory they could all rely on push notifications to know when messages come in but in practice I think a lot of them only use that as a fallback for when the app is not running for some reason. And since the apps are using the network you get a bit of a double whammy because not only are they using CPU time but they are also bringing the radio up as well. So do I bother clearing out Notes and Calculator from the app drawer? No. But if I'm concerned about saving battery I do make sure Sykpe, Palringo, etc. are killed off.