With an external 4TB hard drive, you can expand the storage of your computer or laptop without having it built into the laptop or computer itself. It's also useful that an external hard disk is easy to take with you, so you can also access your data in other places. For example, you can use a 4TB external hard drive to store 112 HD movies of 2 hours, to store 220 music albums, or to store 400,000 photos. This makes these hard drives especially suitable for graphic designers or photographers, who need a lot of storage space.