I'm not sure if there's a limit, but I currently have about 40 'active' saves, and a similar number of 'dormant' ones that I've renamed as backups. I do something similar to what
tangie0906 describes, for example I have different 'set ups' of Sunset Valley such as 'Sunset Valley ST' (Show Time) or 'Sunset Valley SN' (Supernatural). And, yes, you have to be careful to use Save As, so as not to overwrite them. Another kind of save I have are those that I'm using for story telling. These are usually given the title of the chapter I'm currently working on and, when I've finished with them, I move them onto an external back up drive just in case I ever need to revisit them. That helps keep the number of saves to a sane level.
Legend is history as we would like it to be. We pick through the dusts of time for what is worth keeping and, here and there, we occasionally find treasure.