You can make as many or as few partitions as you want. The two things you should not do are:
1. Do not defrag a SSD. Defragging can improve performance similar to a hard drive if the files are too fragmented. But each sector in a SSD drive can only be written over so many times before it fails and it becomes a bad sector. It is not something to be too concerned about though. The last time I've read stats about possible failure rates of SSDs the conclusion was that a modern SSD should last about 5 to 7 year with normal usage (no defragging). A SSD with 100% fragmented files is still much faster than a hard drive with 0% file fragmentation.
2. Do not max out the capacity of a SSD with all your crap... I mean important files. The general...