Defrag - What Is It? How often should you do it?

Here's a question we are asked frequently: "I hear people say I should defrag my computer. What does that mean and how often should I do it?"

Answer: There is a long, complicated answer to this question but we're going to put it in the simplest terms we can. As you add and remove files from your computer's hard drive, the data on the drive becomes fragmented. The more fragmentation, the longer it takes your hard drive to retrieve information.

Let's see if we can give you a practical example of how this works: You are going to Walt Disney World in the morning when they first open. When you drive onto their parking lot, there are attendants who park all the cars one after the other occupying every parking space. However, if you come to the Park later in the day, there are now empty spaces in those rows because people have left. Still, the parking lot attendants will not let you down the rows where there might be empty spaces; they are still parking cars one after the other but in rows much farther from the park entrance. So, by late afternoon, there are many wasted parking spaces. This makes the parking lot fragmented. You can see this in the picture below which really is an aerial shot of part of the parking lot at Walt Disney World.

If the attendants allowed cars to go down all the rows, thus filling up the empty parking spaces, they would, in essence, be defragmenting the parking lot. If you were lucky enough, you might find a spot very close the entrance and you'll get into the park faster. So, exactly what happens on Walt Disney's parking lot is what happens on your computer's hard drive. As all these empty spaces open up from you deleting files, the hard drive becomes fragmented.

Microsoft Windows has a program built-in under System Tools called Disk Defragmenter. This program, when running, moves data from block to block on your hard drive and fills in the empty spaces. Defragmenting may very well speed up your computer. However, one word of caution: slow computer speed due to fragmentation occurs over an extended period of time; if your computer just suddenly slows down, defragmenting will most likely not correct the problem.

Now, to the final part of our question: how often should you defrag your computer. If you Google this question, you'll find lots of opinions from "every week" to "never." Our opinion, based on years of working with computers, is that you should defrag no less than twice a year and no more than once a week. In our shop, our main computer - which has 11 hard drive partitions - only gets defragged about two or three times a year and we probably add and remove more programs and files than most anyone reading this webpage.

One ending note: when you do run defrag, you really should just let it run and not perform any other tasks on the computer.