Originally Posted by gca3020
It would not surprise me at all if Amazon is using cheaper flash parts on the Kindle to keep the price down, so I'd recommend against unnecessary wear and tear like defragging.
I wouldn't expect them to have cut back on costs that drastically that they'd use that type of flash.
Amazon are using a Samsung MoviNAND part as eMMC in the Kindles. It is a flash memory die paired with a MMC controller die all in a single package so from the Kindle POV, it is just a regular MMC "card". I've not been able to find the endurance specifications for this part though oddly enough. I'd expect more than a few thousand erase cycles though.