I always think it's weird to hear people talk about defragmenting all the time. If your computer has to be defragmented more than a few times in the disk's life, something is probably wrong. It's not magic, it just scoots all the pieces which need to be together...back together. And, they only get split apart when you delete some stuff, and save a really big file that can fit into the space you freed, but only in fragments. If you have stuff that lives only a short period, maybe create a special partition just for those files.