iPod defragmentation

Can and should iPods be defragmented and why?
I defragment my iPod regularly. I also read through some forum discussions to hear what people say on this. Below is the summary of my reading and my own experience.

There are two types of iPods - flash memory-based and with regular hard drives. Flash memory is used in the smaller capacity iPods, i.e. nano and shuffle. Flash memories have no moving parts and file fragmentation is not a problem; these do not need to be defragmented.

The following remarks apply to the Windows-formatted iPods which have FAT2 file systems. For Mac, some people use DiscWarrior to defragment iPods, but I am not sure whether that is necessary. I believe that Mac-formatted iPods may have HFS+ filesystem that prevents fragmentation.

Anything above 3 gigs has a regular hard drive, not a flash memory. When the songs are copied onto a blank drive, they are written continuously. If the songs are erased and replaced often, files tend to become fragmented. In order to access a fragmented file, the hard drive head has to move from fragment to fragment, which results in slower performance, battery draining faster, and more wear on the hard drive in the long run, which might considerably shorten its life. Therefore, it is better to avoid fragmentation.

Some people do it by restoring and re-syncing iPod, which is basically a poor man's defragmentation, i.e. erasing everything and copying it anew. A better and faster way to do it, though, is by using a defragmentation software.

The software has to be able to "see" the iPod as a mounted disc. For that, one needs to Enable Disc Use on the iPod. This could be done though iTunes by checking a button named "Enable Disc Use". Even then, some defragmenting software would not see it as a disc, but the WinXP default defragging utility will (Start -> Programs -> Accessories -> System Tools -> Disc Defragmenter). It can generate a report of how badly fragmented your iPod is and whether it is time to defrag it. If the iPod is full to the capacity, the program might warn you that no less than 15% of free space is needed for the defrag. It is possible to defragment with less than 15% free space, but it may considerably slow down a process which is rather slow already.

If the battery dies during defrag, files will be corrupted and lost. Before beginning, make sure you are using a powered connection - either a USB2 port, or a double cable to USB and the power outlet. Defragmenting an iPod which is not powering up during defrag is generally a bad idea.
Also, defragmentation may take a while; all this disc activity together with battery charging may heat up the iPod significantly, so it is better to take it out of the protective cover, if you got one (and you should!), and lay it on an open surface.