About a week ago, I posted a guide on the various ways to keep your iOS device in top shape. In the post, I suggested killing off apps in the multitasking bar:
Unfortunately, multitasking can seriously put a strain on your battery life, and more importantly affect the performance of your device.
I was wrong and misinformed about how multitasking actually worked.
Here’s the tl;dr explanation:
The iOS multitasking bar does not contain “a list of all running apps”. It contains “a list of recently used apps”. The user never has to manage background tasks on iOS.
In other words, when you hit the home button to close an open app, that app does not continue to run in the background, draining memory, consuming CPU time, and sucking your battery life. The only exception to this constraint are apps that fall under five distinct categories:
- Apps that play audio in the background; ie, Pandora.
- Apps that track your location in the background; ie GPS navigation apps.
- Apps that listen to incoming VOIP calls; ie Skype.
- Newsstand apps that are downloading new content.
- Apps that receive continuous updates from an external accessory in the Background.
One perfect example of an app that fits one of these categories is the Mail app. If you hit the home button while Mail is still downloading your latest emails, the app will continue the download while running in the background.
This explanation is supported by Apple themselves in their guide on “Understanding multitasking.”
Speirs goes into the further technical details of the various states of iOS apps. Check out his entire explanation here.