I know a little about how iOS handles memory on the iPhone but my questions relate to if it is necessary to close an app once you are done using it. If it is not closed, does it continue to use up memory running in the bg? It is very time-consuming to have to swipe up on all of the applications that you want to quit running. But if the operating system knows that an app is idle.. is that still taking up memory? I'd like to understand more about the entire process.