bobfrost said:
Not according to Microsoft who design their OS to work on ssds and hdds. They say that the file system records used by the ssd need fragmenting about once a month, and they do it as part of the OS maintenance program. The file system records have a max capacity of fragments it can record, so needs defragging to keep the number of fragments within the limits.

Bob Frost
That's completely different system of optimization and is not to be confused with HDD defragmentation. OS works in conjunction with FW built in SSDs to do whatever is necessary to keep an SSD in shape, mainly thru TRIM operation.
Although file system on SSD appears identical to HDD, it's just logical arraignment for compatibility and files on SSDs are stored in much different way.
Actually, even on HDDs data is stored in a logical way that is not identical to physical arrangement on them. When you add spare blocks and over-provisioning to all of that, things get even more complicated.