One thing you have to understand, vodoun, is I live in Houston, on the Galveston Bay. It may be January, but even inside, my place averages 75 - 80 degrees with a high degree of humidity (my apartment's insulation sucks). The only issues I've seen are with the ab armor, and I suspect they arose because of the rubbing I did on that area when I fastened the belt, as well as when I was trying to clean a couple of scuffs off the rubber. Until I actually started rubbing it, the ab armor was fine. Of course, then I started ____ing with it even more, which led to more paint rubbing off.
I don't think environmental factors will do all that much, if anything, to the figures that did not have any defects out of the box. Then again, I could just choose to be pessimistic and expect everything to fail, but I prefer not to think that way.