The process of managing memory on your device have drastically changed over the years. You may remember having to run a memory manager that would warn you if too many programs were running and allow you to close the program eating away at all your available memory. This has changed because memory is cheaper and abundantly available combined with smarter operating systems that handle this mundane task for us.
Even though the operating system that powers the iPhone, iPad and the iPod Touch manages memory for us, I still see people swiping away apps to close them one by one. We feel empowered as though we are helping solve a problem that in fact we may be making worse by performing this action – battery life and speed.
A common misconception is that iOS apps run in the background and take up memory, therefore decreasing battery life and speed. iOS apps do not run in the background unless you have Background App Refresh, which allows apps to periodically wake up to perform a quick task, enabled or they are performing certain task allowed by iOS to run in the background. Once you close or switch to another app, iOS intelligently saves an application state and if needed frees memory. The app is not running even if seen in the fast app switching interface.
This list is not a list of running apps but of recently opened apps. Since iOS automatically handles memory management, closing these apps actually can use more battery life. If you close these apps the next time you open them it will actually take more power and resources because the saved state has been removed, requiring a full launch of the app.
In other words, stop swiping apps to close them and just use your device and trust it will do the mundane task of memory management for you.