Hi beginpsrsx900,
Flash memory storage devices such as USB sticks usually do NOT need to be defragmented. Nevertheless, it can happen that the performance (i.e. reading speed) decreases over time, e.g. if files are stored on the stick in a highly fragmented manner (i.e. in many small "portions"). If necessary, the data can be temporarily moved to the computer and then copied back to the USB stick. (The stick can, but does not necessarily have to, be reformatted.)
By the way, the Defrag feature of current Windows versions can now also deal with flash memory devices and SDDs (and "optimize" them if necessary).
Best regards,
Chris