… A Guide to Better Battery Life
If you have an iPhone, an iPad, or an iPod touch, you have doubtless heard that you can extend your device’s battery life by double-clicking the Home button and swiping up and away all of the apps that appear in the multitasking window. This is true sometimes, but certainly not the majority of the time. Allow me to explain.
Your iOS device is a small computer. Like any computer, it has a processor; “permanent” memory for storing photos, apps, and other material; and fast temporary memory (aka RAM) for storing what you are working on at the immediate moment. As soon as you tap an app on the Home screen, the app launches, loading all the necessary information from permanent memory into fast RAM so the app can respond to your input. This information stays in RAM unless you double-click the Home button and flick the app out of the multitasking window to force-quit it. At this point, all its information is removed from RAM, and the app is no longer running.
So yes, it’s true that when you press the Home button to get out of an app, the app’s data remains in RAM. This allows the app to launch faster if you decide to go back to it right away. But the app is no longer running. It stays in the background, paused and waiting for you to come back to it. Since the app is not running, it is not consuming any battery life.
You might think, “So what? What’s the point of discussing all this?” There is a reason. When your device loads information from permanent memory into RAM, it uses a relatively significant amount of battery for a very short period of time. If you force-quit the app and then launch the app again soon, the device must re-load that information (which it would not have had to if the app was still in RAM), consuming more battery life again for a brief moment.
The thing is, you don’t need to clean up after your device. When RAM fills up and it needs more space, it removes the oldest data by itself to free up space for the current task. So you don’t have to worry about force-quitting apps because your device takes care of itself.
The exception to this rule includes apps that do run in the background, like Facebook while it’s gathering new posts or navigation apps that use GPS to keep you on track while you are using another app. Force-quitting these when you are not using them prevents them from gathering data in the background.
It’s not necessary to force-quit apps on your iPhone, iPad, or iPod touch. Force-quitting apps can even negatively affect battery life, so the practise is best avoided.