Going beyond just carrying a spare in our RV (inflated to the highest needed pressure -> that of the rear duals), I also bring along in our small Class C motorhome:
- A 12 ton high lift jack in case the earth is so soft under the jack that it has to be extended aways to actually lift anything,
- a lot of blocks to put under the jack and the tires as further protection against soft earth and for safety to support the axle when chainging a tire,
- two cans of truckers tire inflation canisters in case one isn't enough or for redundancy in case one goes bad during storage,
- a professional quality puncture repair kit in case a flat tire is merely from a small hole ... so why mess with changing the whole tire,
- a full power 120V AC compressor that can be powered by the built-in generator,
- membership in at least two ERS plans in case one gives me too much grief,
- and a satellite communication device and medivac plan to go with it ... to get ahold of ERS for vehicle help or for a medivac helicopter for medical help ... when our cell phones won't cut it.
I was never a Boy Scout and I was only a U.S. based captain in the AF ... but I don't care much for having to only rely on others to be around to help get out of trouble.
I guess it boils down to "hope for the best, but prepare for the worst".