If you’re a normal computer user, meaning you use your computer for web browsing, email, gaming etc. for less than eight hours a day, defragmenting once a month is often enough.
If you’re a heavy computer user, meaning you use your computer for more than eight hours a day for work, you should defrag your hard drive more often, about once every two weeks. As a general rule, any time your disk is more than 10 percent fragmented, you should run the defrag process. You can check the percentage in the Current status column of the Optimize Drives window.