I had read once here :
Defragmenting all the fragmented files before CCleaner means that larger contiguous areas will be released for use instead of more and more, and smaller and smaller free spaces being produced. This holds true for my System volume files as well. I end up with larger free space areas in many places on the disk. I don't defrag the whole disk because then the first files to be changed or added must be put only to the inside of the disk. This area is slower and results in constant head movement. Whereas, having many large free spaces all over the disk results in less head movement.
that defragmenting files is a better practice than defragmentic free space vis-à-vis performance, and took this advice to heart. This would imply that, for instance I first run Defraggler and then CCleaner (so the defragmented files that CCleaner will delete will result in free space fragmentation which presumably will result in less head movement - see quote). What you say ? Is it best to have defragmented files and fragmented free space or contiguous free space ?