Neven Mrgan's tumbl: Don't play The Tray
Trying to “clean out” your tray is not a habit you want to get into. It’s pointless, and besides, you can never win - as soon as you run another app, in the tray it’ll go. It’s like the world’s worst game of Whac-A-Mole. Instead, learn to see the tray as a “recent apps” area. If you’re in the middle of one task - say, writing an email - and you need to switch to something for a second - say, looking up a spelling - then the tray is your friend. But once you’re done with that, you’re done.
I was horrified when I first saw the tray; how am I going to make time for that without neglecting my inbox and trash can emptying duties?