Hi Richard,
None, really. However, you might get confused as to which version you are
looking at, so be careful with it.
As I said, I rename to base subdirectory to <subdirectoryname+date> - eg,
mysys030104. The solution name is still the same - and since all kinds of
things point to it, it really has to be the same. I tend only to reopen a
saved system if I need to recover something that I might have changed but
shouldn't have, etc. The I copy the code I need, reload the original, and
paste as necessary.
Bernie