(old)Puppy Linux Discussion Forum

Fragging wonderful: The truth about defragging your SSD

...My tests showed little or no benefit from running a number of disk defragmenters on a heavily used SSD.

SSDs do dynamic wear levelling (traditional hard drives don't do anything, and Flash based memory cards and I think USB thumb drives do static wear levelling), which means if some of your files aren't changing they move them around so that they wear out all of the parts of the disk at about the same time.
It seems to me that if you defragmented an SSD you'd be fighting against the dynamic wear levelling.