I want to clear up some misconceptions about your apps running in the background. I even know several people who have gotten very bad information from Apple Store employees about this. If you “terminate” your apps when you are done with them you are wasting your time, and very possibly slowing your iPhone down. Let me explain.
In multitasking, if you see a task manager, they blew it. Users shouldn’t ever have to think about it.Steve Jobs announcing the multitasking feature of iOS 4
In the past, back when our computers had limited amounts of RAM (“memory”) and computers weren’t as smart as they are today, we were obsessed with making sure that we quit programs that aren’t being used. We sought to have as much free memory as possible for any new program to come along and use it. Now we have smarter ways of managing memory, and many programmers have a new saying, “unused RAM is wasted RAM.” The idea is that if you leave an app, the computer doesn’t necessarily remove it from memory in case you open it back up again. But if another app comes along and needs some memory, the computer can decide what to remove to make way for the new app.
In iOS, double tapping the home button brings up a list of recently used apps. Despite what you might have been lead to believe, this is not a list of currently running apps. When you leave an app, it does not continue running in the background (except for some rare cases such as playing audio, GPS navigation, and VoIP apps such as Skype). It is suspended in memory, but only until another app needs the memory. That way if you decide to return it’s desuspended and ready to go.
So why does Apple let you tap-and-hold on the list of recent apps to start killing them? One reason: restarting crashed apps. Sometimes iOS doesn’t realize that a poorly behaved app is frozen, so the easiest way to restart the app is to manually terminate it.