If your phone storage is always full - looking at you, picture hoarders - and you don't want to pay for more cloud space, try Google's Files Go app. "Files Go will detect duplicate files, recommend uninstalling unused apps, recommend deleting app cache, as well as large files. Underneath each card is the amount of megabytes (or gigabytes) you can free up if you delete the suggested content." It is highly customizable and offers other features, such as transferring content. Maybe you'll finally be able to download your entire Spotify library!