SP, I wouldn't - if what you do creates new fragments, it will be a never-ending story.
What are you using as a defragger? I use the free one from
http://www.auslogics.com/en/software/disk-defrag/ The first run on a badly fragged disk can take a while, since it depends on the amount of free space available for shuffling the pieces and putting them together again into complete files, but once that is done, a regular defrag only takes a couple of minutes at the most.
If yours is taking all night, I would say something is wrong.
Cheers
MikeW
Mike Im using ultimate defrag , it took all night to do 4 hard drives and is 1 hr away on the last one now.
Im ashamed to say ..... i have to admit its been two years since i did it last , and that was imcomplete