to stay, to move, to improve

This old house in Monterey got an indoor bathroom upstairs in 1953, thanks to my parents.  When my father could no longer go the stairs, he had a commode installed in a closet downstairs.  We took that out in 1988 when we moved in with strong legs and two kids.

Assuming we should have a bathroom downstairs (and we so assume), the big debate is whehter to build on or put a half bath in existing space.  I wrote down pros and cons to help me think it through.  It helps. It did not solve the issue.