If you’re an iPhone user, you may have been told you can save battery life by force-quitting apps that you aren’t using. And it seems logical, because “cleaning things up” is normally a good thing, but in this case it simply isn’t true; in fact, it’s quite the opposite. This topic has been making the rounds on the Internet for a while now, but I think it’s been overcomplicated, so here’s just what you need to know.
First, let me be clear what I mean by “force-quitting”. It is the process of double-tapping the home button and swiping up to remove apps from the app switcher screen1.
The apps that you see in app switcher list have either been suspended because you switched away to run a different app, or they’re actually doing something you told them to do in the background. For example, you might start up Apple’s Music app to play music while exercising, but during your workout, you stop to find something on Amazon using Safari. The music continues to play in the background even though you’re not directly interacting with the Music app anymore. If you then switch to another app, maybe to check the weather, Safari becomes suspended.
Obviously, force-quitting an app that is actively doing something will save battery life, but most apps don’t fall into this category. Most go into a suspended state, and when they do, they no longer use battery, processor time, or network connectivity. They use just a small amount of memory that allows them to be quickly restarted when you switch back to them. In the event your iPhone runs low on memory, it will automatically remove suspended apps as necessary to find the space it needs.
What’s not obvious is that when you force-quit a suspended app, you actually trigger a slew of processor, memory and disk activity that saves the state of the app and formally closes it down, all of which uses battery power. And since we know that the phone cleans up suspended apps when it needs to, force-quitting ends up accomplishing nothing other than using more battery power, not less. And of course, the next time you want to use the app, instead of being quickly restarted, it has to be loaded entirely from scratch using even more battery power. So the take-away is this:
The only time that force-quitting is truly necessary is when an app freezes, or is somehow misbehaving.
Actually, there could be one other time. If neatness and orderliness are more important to you than battery power, force-quitting may be a Very Good Thing.
The app switcher is sometimes referred to as the “Chooser”.↩