Disk Usage is a very straight forward app. I won’t even go in to much detail other than: it’s free, and VERY helpful. Want to know why you have such a small amount of free space on your phone’s internal memory, or your SD Card? This will graphically display your files and apps so that you can easily track down what the biggest files are and decide if you want to uninstall the app or just delete the files straight away. You can zoom in by clicking in to each ‘directory’ and it will expand to show which files are taking up the space. It’s so easy to use and so useful – you should go get it. Now.