Adding a hard drive to your desktop computer isn't as difficult as it sounds, but does require some work. Unfortunately you can't take it with you if you need to access the information somewhere else; that's where external hard drives have the advantage. There are different types of this hardware, all presented here in this buying guide.
There are two different types of external drives: enclosed ones and internal drives in an enclosure. Enclosed drives are sold already in an enclosure; it isn't meant to be opened up, and are generally slightly slower than most internals. They connect to your computer via USB cable. Internal drives in an enclosure on the other hand are just what they sound like: you buy an internal hard drive, as well as an the enclosure. The enclosure hooks up to your computer via USB cable as well, but it means that you can remove them as needed. Both are quite portable.
You'll get the same advantages with either one, though by design the internal versions will likely last a little longer and write to disc a little faster. The main function people use for external drives is for back-up purposes. Because externals often come in high capacity (some drives as high as 2 terabytes), they're optimal for this kind of purpose.
They are also advantageous for laptop users; laptops are getting more and more disk space, but still have far less capacity than a desktop. External types are ideal for storing photos and music, while still being very portable due to their increasingly small size. Even if your laptop has a high storage capacity, storing large amounts of data can sometimes slow down the speed of your computer. External hard drives allow you to keep your laptop disk space largely free while still allowing you to take everything with you.
External hard drives give you a lot of flexibility. You can choose to back-up your files and keep your external drive aside, or use it on a regular basis to store photos, music and movies. Whatever the case, external hard drives give you plenty of options and is a wise investment.