A few weeks ago, I asked users of Apple's iOS devices to share the tips they would give people who were new to the OS. Lots of useful suggestions came back, via Twitter, but several people said that new users should be told that it's important to quit apps that you aren't using. I was surprised by that because, as far as I knew, it isn't true.
The theory is that forcing apps to quit - by double-tapping the Home button to open the multi-tasking menu and, on iOS 7, flicking the apps up off the screen - you will free up system resources and minimise battery drain. It seems that a lot of people consider that to be a pro tip.
Unfortunately, it doesn't work. Once you switch away from an app in iOS, it is suspended. iOS remembers the state it was in when you left it so that you can go right back to it on your return, but the app is not actually running anymore. The only exceptions to that rule are apps that have some background functionality, such as streaming music apps or apps that can upload files in the background. However, even those will be suspended after a certain period of time.
If an app is malfunctioning then, yes, forcing it to quit is the answer. But in normal use force-quitting apps will not make a difference. Explaining this can be difficult because some people simply do not believe it. They swear that they have seen an improvement in the performance of their device after doing it. All I can say to those people is that they are mistaken. I've checked with Apple and I've checked with independent developers and the answer is the same: force quitting apps will not save battery life or improve performance of the device.
In an attempt to combat the misinformation I've added that as one of my iOS Tips and Tricks in the Guide to iOS 7 that I have written in collaboration with Touch Press. It's the first Touch Press iBook and it's free so if you're an iOS 7 user then I recommend downloading your copy now.