If your iPhone battery seems to be dying faster than usual, it's natural to blame all the apps you have open then double click the home button and start swiping up to close them, but it turns out you are doing more harm than good!
Technology writer and expert John Gruber wrote a post explaining why it is worse to force quit:
Apps in the background are effectively 'frozen,' severely limiting what they can do in the background and freeing up the RAM they were using. iOS is really, really good at this. It is so good at this that unfreezing a frozen app takes up way less CPU (and energy) than relaunching an app that had been force quit. Not only does force quitting your apps not help, it actually hurts. Your battery life will be worse and it will take much longer to switch apps if you force quit apps in the background.