Danbo is right. At work, when we want to wear stuff out that goes on airplanes, we shake em and put them through repeated temperature extremes, Shake and Bake, as it were. You can accelerate normal aging real quick that way.
I think this means that if you reduce the rate of change of temp on your units, and try to avoid dropping them on their haid, you will do some good in making them last.
Note that the factor here is how quickly they go from cold to hot to cold, not what the temperature extremes are. You might totally fry your unit by bringing it inside from -30 to a nice warm room, and setting it by the fire to 'warm up'. Not a good idea. Warm up the batteries if you like, but don't turn your hairdryer on the gps if it has been cold. Gradual changes in temp are best for electronics.