I’ve been hearing a lot of people, particularly in the comment sections of tech news sights, complaining that they didn’t really need multitasking, and that they’re now spending all their time “killing” apps in the popup dock in order to conserve battery life.
Hate to break it to you, but Apple’s implementation here isn’t hurting your battery life. Think of those apps down there as a “recents” list, not a “currently running” list. Because unless those apps are specifically running one of the new background services (like audio playback, etc.) they aren’t “running.” They are temporarily frozen in RAM, but they are not eating processor cycles, slowing down your phone, hurting your battery, etc. In fact, any app that hasn’t been recompiled specifically for iOS4 isn’t even frozen in RAM. You don’t need to kill any of those apps, because your iPhone will kill them for you as needed. That’s the whole reason why we waited this long for Apple to implement this solution.
The only reason to “kill” one of those apps is if you specifically need it to reset itself for some reason, or if you don’t want someone else to know what you’ve been running lately. Otherwise, leave that drawer alone; the device will take care of everything for you.