Desktop hard drives continue to be one of the best solutions for adding storage capacity to a PC whose internal drive bays or connections are maxed out. It is always easier and cheaper to add an external hard drive rather than trying to add internal hard drive space.Desktop hard drives designed for home use or small businesses typically offer capacities. Many people choose to mirror the hard drive on their desktop or laptop computer. Mirroring a drive means you copy everything including software - so in the event your entire system crashes, you can re-create your computer from scratch. Desktop hard drives offer the capacity you need to mirror effectively.