Frasier Speirs:

There is one iOS "tip" that I keep hearing and it is wrong. Worse, I keep hearing it from supposedly authoritative sources. I have even heard it from the lips of Apple "Geniuses" in stores.

Here is the advice - and remember it is wrong:

All those apps in the multitasking bar on your iOS device are currently active and slowing it down, filling the device's memory or using up your battery. To maximise performance and battery life, you should kill them all manually.

Wrong. Wrong. Wrong. Wrong. Wrong. Wrong. Wrong. There are caveats to this but anyone dispensing the advice above is clearly uninformed enough that they will certainly not be aware of these subtleties.

Thank you. I can not stand when "common knowledge" is wrong in such a way that it causes most people to do more work than necessary for absolutely no gain. Speirs explains with technical detail exactly why this is. I can not tell you how many times I've tried to explain this to people, technical and untechnical alike. Thankfully, I don't need to explain it any more, as he does so perfectly. If you want to know the details of why, read his post. Otherwise, the intro should suffice along with his conclusion:

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