Not a terrible question.

I have my old pair in my BOB. They're several years out of date, but "good enough" to get things done: drive, cook, see something out in the distance. I won't be winning any awards for seeing a deer at 1000 yards or anything, but it should be OK.

I actually wear contacts too. I keep a travel size contact solution bottle and spare case at work. I have the mandated 2 spare sets of glasses that my job requires, though they're actually too strong and I stick with my regular pair of slightly out-of-date lenses (notice a recurring theme here?) when not wearing my contacts.