Well, I DO keep my supplies out of the sun and heat (if you count on the tile floor under my sideboard because that's the only place I have to store it) so, by default, I suppose I do do that.

As for the plastic wrap - I need to caution against that. I don't do it because if you do detail work, the wrap will mush everything down and mar your work. I can see the need to keep the clay from pet hair (as anyone with a cat can understand), but plastic wrap would be worrisome to me.

I just keep my works in progress up on the shelf until I can get back to them, and I've not had any problems whatsoever. But that's me. I haven't published any books on it.