Ever since multitasking was introduced in iOS 4, there’s been a misconception that by closing all apps in the multitasking switcher, you’ll save system resources. The truth is that only few apps run in the background, so most of the apps in the switcher do not necessarily consume system resources.

However, with iOS 7’s smarter multitasking, the type of apps that can run in the background has significantly increased, so you might be able to see a clear difference in battery life if you keep closing apps, especially ones that have permission to run in the background.

In iOS 6, these types of apps were able to run in the background:

• Audio: Pandora, Podcasts, Instacast, etc that stream music.
• VoIP: Apps like Skype that let you be on a voice call even after you’ve closed the app.
• Location: Navigation apps to continue to guide you even when you’ve closed the app, geo-fencing apps like Moves, Reminders etc. that have location-tracking or location-based alerts
• Newsstand apps like The NY Times that download new content.
• Apps that receive continuous updates from an external accessory in the Background.

iOS 7 includes a feature called “Background App Refresh” that allows apps to refresh their content in the background, so apps wake up periodically, and download the latest content just before you are likely to open it. The company has obviously put in a lot of effort to optimise performance, as detailed in our overview of iOS 7 multitasking, but you’d still save system resources if no apps were refreshing in the background. The trade-off would be that you’ll have to wait for new content to appear after you open the app.

If you kill an app running in the background from the multitasking switcher, it can’t wake up in the background to fetch new content, thus saving up on network, CPU cycles, and of course battery.

So the right answer to the question “Does killing iOS apps help your device” is “It depends.” It depends on what type of app is it, how often it wakes up in the background, and even how often do you use the app.

Some popular iOS apps that take advantage of the new multitasking modes are:

• Pocket, the read-it-later app that updates your queue in the background when you add a new item.
• Twitterrific, the Twitter client that refreshes your Twitter feed in the background periodically.
• Instapaper, which again updates your read-it-later queue from time to time.
• Flickr, that auto-uploads your photo library to the cloud in the background.

And a lot more!

To see which of the apps on your device refresh in the background, head to Settings > General > Background App Refresh.

Of course if you don’t intend on using background refreshing, you’d be better of disabling it from here, rather than closing the app from the switcher each time after you use it.

If your iOS device’s battery life is draining quickly, then it is possible that it is due to a badly written app, so you may have to kill apps one-by-one from the app switcher to find out which app may be causing the issue [How to kill an app or apps in the background].

Do you kill apps running in the background? Let me know in the comments.