There's a big misconception people have about closing apps on the iPhone.
I see it every day. Someone is standing in line to get coffee or waiting for the next train, and they start swiping up on all of the apps in their iPhone's multitasking switcher - the list of apps you see when you double tap the home button - to close them.
I understand the idea psychologically. Swiping up removes the app from the switcher, effectively closing it until you reopen it again. That should make your battery last longer because a bunch of apps aren't running in the background, right?
Except that's not actually how apps on the iPhone work. Swiping up on everything is a waste of time. And you don't have to take my word for it.
Apple's head of software, Craig Federighi, confirmed that swiping up on apps doesn't save battery life in an email to a customer earlier this week. The email, obtained by 9to5Mac, is short and sweet:
Customer: Do you quit your iOS multitasking apps frequently and is this necessary for battery life?
Federighi: No and no.
iOS, the mobile operating system that the iPhone runs, is actually smart enough to kill apps on its own. It has been for years. This isn't to say that there aren't times to manually close apps. But "generally, there's no need to force an app to close unless it's unresponsive," according to Apple.
"Some apps will run for a short period of time before they're set to a suspended state," Apple's documentation reads. "This means they're not actively in use, open, or taking up system resources. When you return to these apps, they'll open instantly."
So unless you have OCD and just can't sleep at night without clearing out all of your apps, there's no need to constantly swipe up.
The only case where closing apps could prove useful is if a buggy app is forcibly staying open in the background and draining your battery. This could apply to something like a maps app that needs to stay open to track your location, but once its job is done (i.e. your trip is over) it should close on its own.