My first rule of thumb is, "Don't move stands in the middle of the season". Second rule of thumb is, "Rule number one gets broken sometimes". If you've lost all confidence in your location then consider moving it. If I absolutely have to move a stand, I like to do it in the rain, or with rain in the near future. I think this helps wash away the scent that you leave behind while trimming shooting lanes, moving the ladder, standing around choosing the right tree, etc.
I will also echo what Night Wing said. Multiple stands in multiple locations.