I have been fortunate enough to have my stuff mostly in a controlled, dry, cool basement through most of my years. The stuff I had I had in more "exposed areas" like a garage has mostly survived, but I have noticed warping on some of my older POTF2 stuff that was exposed to extreme temps.
Do you have any opportunity to move your other storage out into the garage? I have to think that ornaments and cake pans and crap can weather the garage environment better than your toys. Maybe build up some cool, easy access shelving in the garage to get your wife on board with it, then you have more space to work your toys or other stuff into.