What you should really try to avoid is frequent swings in temperature and humidity. So avoid setting the bass where hot air may blow directly on it or radiant heat may reach it or overly damp or overly dry air may come in contact with it.
A hard case (or to a lesser degree a gig bag) is a good container for your bass if it's not frequently used. It keeps dust and dirt from settling on it, keeps dings and chips to a minimum and slows down temperature fluctuations.
If I wanted the bass in a stand and not a case I'd put it somewhere in the room where there is not hot or cold air blowing on it, no sun directly hitting it and no chance of moisture getting on it (i.e. away from a window and away from a space heater).
Or you can just give it to me and I'll take care of it for you.