+ 0 Votes To defrag or not to defrag? mjd420nova 6 years ago I usually go with what the system says as to whether to defrag. I run disk cleanup, spyware, spybot and virus checks weekly on all my units and if needed or recommended by the system, a defrag. Going for extended periods without a defrag can take a long time to complete and might overheat the drive. If left for too long, there might not be enough room on the drive to do an effective defrag or have to break the files into smaller pieces thus taking extremely long periods to complete the process.