What I mean is... The 1st time you run a defrag it takes a bit, the 2nd time you do it, it takes less time because it`s been defraged, the 3rd time you do it it takes even less time. You want to run it until it`s done in just a few seconds. After that, if you want you can put it on a schedule.
I have always run a defrag manually on hard disk drives.