there have been about 10 threads on defragmenting in the last few months, just do a search and you'll find them. people get way to concerned with defragmenting and repair. fragmenting is not that big a deal on the hfs+ filesystem and as long as you keep about 1-2gigs of the drive free and have enough ram to keep page-outs to a relatively infrequent ocurance, you should not have any noteworthy defragmentation issues. windows tends to fragment itself quite often and easily, as well as requiring lots of disk repair. under osx, you shouldn't have too many crashes (if any at all) and any problems with the filesystem are corrected when you boot the machine (and now you can enable journaling if you are that concerned about your hd). people need to get out of the habbit of running disk utilities and defragmenters every week because they think that it's necessary. it's not necessary, one of the good things about unix is that it's built to be stable and low-maintainence. defragmenters for the mac are kind of a placebo, since anyone who would cause serious defragmentation (like people using the hd as a scratchdisk for huge video and photo projects) should just erase the disk every so often.