Yes of course - you defrag a regular Winchester drive because the files become fragmented - requiring extra head movement and disk rotation to read them. Sometimes multiple operations. With a solid state drive there is no head movement and consequently no wasted time.
A regular drive takes average seek time plus half the time of rotation to get to the next spot on the disk - a solid state drive does not have this drawback - no moving parts.
However... Wikipedia says...
There is limited benefit to reading data sequentially (beyond typical FS block sizes, say 4 KB), making fragmentation negligible for SSDs. Defragmentation would cause wear by making additional writes of the NAND flash cells, which have a limited cycle life. However, even on SSDs there is a practical limit on how much fragmentation certain file systems can sustain; once that limit is reached, subsequent file allocations fail. As such, defragmentation may still be necessary, although to a lesser degree.
generally No defrag required, December 2015
