I would say it depends on the size of the SSD, the amount of data and your data structure. Of course basically as much as possible of your work files on the SSD. Durability shouldn't be a problem at all at these data rates.
I have all my data files (project files, documents, textures, models, materials, installers) stored on my file server. My recent projects and presorted textures and models on a 500GB SSD on the server (in RAID1). And the rest on HDD. All backuped to HDD. (so the network connection is the limiting factor)