fayans said:
Actually, I should clarify - when i I was saying "everyone should do it", I was referring to general maintenance tasks, not defragging specifically. So what you're doing then is great, and I wouldn't worry. Although I defrag, it's just more of my own choice, and in fact, I would argue it isn't necessary on a Mac. All the other things I mentioned above are important, but defragging isn't a necessity, let me clarify.
Hard disk capacity is generally much greater now than a few years ago. With more free space available, the file system doesn't need to fill up every "nook and cranny." HFS Plus avoids reusing space from deleted files as much as possible, to avoid prematurely filling small areas of recently-freed space.
In general, fragmentation is often caused by continually appending data to existing files, especially with resource forks. But now, with faster hard drives and better caching, as well as the new application packaging format, many applications simply rewrite the entire file each time. Panther can also automatically defragment such slow-growing files. Aggressive read-ahead and write-behind caching means that minor fragmentation has less effect on perceived system performance.
For these reasons, there is little benefit to defragging.
