If you use Windows, then it is crucial that you defragment your hard drive at least once per month. However, if you are like many users, you don’t even know what defragmentation is.
In actuality, it’s not important that you understand how the NTFS filesystem fragments over time; instead, just know that it does, and there are steps you should take to maintain your system.
Think of it as changing the oil on your car every 3,000 miles.
Fortunately, there is a free program called JKDefrag, which is the best freeware defrag program I have found.
Hope it helps!