With an external 1TB 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 1TB external hard drive to store 28 HD movies of 2 hours, to store 110 music albums, or to store 100,000 photos.