The official YouTube app pauses audio whenever you switch to another app. Sometimes you only want to listen to the audio of the video, and it’s quite frustrating to keep the screen on and the app active. Music videos or interviews, for example, can be enjoyed through the ears. Fortunately, there is a solution to listening to YouTube videos in the background. It’s not the most elegant solution, but it does the job.
Firefox for the win
I use Firefox for Android to listen to YouTube videos, because the official YouTube app doesn’t allow multitasking (audio pauses whenever the app isn’t active). There are other ways, but I think this is the easiest.