How iOS multitasking really works

There's one bit of iOS misinformation that I keep hearing. Even supposedly authoritative sources just as Apple Geniuses don't seem to get it. It has to do with how multitasking works in iOS.

App that downloads largish files from the Web

Let's take an app that downloads largish files from the Web, just as Instacast, my favorite podcast app. When Instacast is Active, it can start to download new podcasts. By default, if I hit the home button on my iPhone, Instacast would get five seconds to run in the Background state earlier it would be moved to Suspended. That would interrupt the download of my podcasts, which can take some time.

Apps that listen for incoming voice-over-IP calls. If you use Skype on iOS, you can receive incoming Skype calls during the app is in the background.

Five classes of apps-audio, GPS, VoIP (Voice over Internet Protocol), Newsstand and accessory apps-and some built-in apps just as Mail may run indefinitely in the background until they complete their task.

Put simply: You do not have to manage background tasks on iOS. The system handles nearly every case for you, and so then-written audio, GPS, VOIP, Newsstand, and accessory apps will handle the rest.