I've kept mine in the little cuppy hole for 4 years and the elements have not ruined it. The plastic is a little yellow from aging. When I take it in the house to look at it I will invariably forget about it and then end up needing it. I think there is a point to it. There are some mechanical instructions in there about the chain, tires, fuses etc. that could come in handy if you broke down on the road. Then again someone could swipe it.
As far as air. I don't use it. I have the new airless Michelins on my bike
