So to clarify whether defrag must be done or not.

A client of mine came today and told me that he had defrag its 32gb usb stick, but he noticed no difference in speed.

A defragment hard drive, make better performance and makes it faster to read data from disk.

But this is not the case USB flash drives.

To a hard drive is faster to use after a defragmentation because it works with a moving head. The more scattered data on the disk makes the head to moving more and therefore its being slower.

But for flash memories its works quite different because they have no moving parts. However, they have a limited life.

USB flash drives and memory cards can only handle a certain number of rewrites before the memory cells become exhausted.

However its thousands of rewrites, but sooner or later, the cell will die.

To defrag a storage card is therefore not a good idea.

it will not make the use of it but its life will be greatly reduced.