Maybe I'm hard on tires, but I've used a spare tire on tour so I'll likely carry one in the future.
I've got a folding tire for future use, but only as a spare. I found a folder without much tread (which keeps the weight down) that's about 700Cx30. If, or when, I use it, I'll replace with a heavier tire at the nearest bike shop that carries touring tires, 700cx32 or 35.
I know that sounds backward; why put on a heavier tire? For me, it's the extra tread thickness, translating into extra tread life, or further until I have to replace the thing. The replacement tire will probably be wired, depending on what Podunk Bike Shop has in stock. Wired is nearly negligible for extra weight, but shaves a fair bit off the price. I'll normally spend $30-40 on a wired touring tire, but the folder costs nearer to $60.