I'm in the "I don't care about the spare" category. The last flat I had was as a teenager in 1972 on a motorcycle I bought from a friend for $100. But I do always replace my tires early and check the pressure and tire wear regularly.
If you're talking about the motorhome in your signature, the F-450 is very common and, should you need a replacement tire, will be easy to find. If you buy and carry a spare you have to remember to replace it every 7 years. If you're constantly replacing unused tires because of their age, that's wasted money. If I happen to need a tire on the road, even if they charge me double the going rate, I'm still way ahead on money.
So, no spare (or roadside assistance plan, or extended warranty) for me. I self-insure on everything, and over the years I am way ahead financially. On the rare occasion I need something, I rely on a credit card and the promise of a really good tip to the person taking care of me.