How does one go about telling if it is dead or not? I run all weathers in late spring and summer, and put winters on in late October, so the real spare gets swapped at the same time. I also don't put a lot of miles on my car, my commute is fairly short- should I be worrying about tire age as well as road miles?

I'll look to see if I have any pictures scanned of my Grandfather's "bush truck" when he worked in Liberia- he had a rack of four spares, with jerry cans of fuel and water under it on his pickup. Although those roads were only barely worthy of the name.