Save time! Jim Hamm tells us how. "You've probably read/heard that it's not necessary to do a defrag on a Mac running OS X. Here's a video that clearly explains the mechanics of de-fragmentation and why it isn't necessary in OS X."
You'll find MacMost has 739 videos! Click on the small box under the title for the listings. This one takes less than 7 minutes, and it's well worth the time.