We carry an unmounted spare for our Class A DP. It's the reason we bought the toad we did. . . need 39 inches in the back end to carry the tire. Few toads can qualify.
The only time we needed one we took a nail in a relatively new tire. The road service had trouble locating a service who would replace the tire for less than outrageous prices. So after sitting for 6 hours, we finally got someone to come and put on a used tire. He wanted to take our tire since it was ruined. We said no thank you. Drove 22 miles afterwards and spent the night in a tire shop lot. In the morning, they removed and threw away the tire the service had put on. It had a sidewall repair. . .bad news. . . They plugged and patched our tire, put it back on and it ran for 40,000 more miles.
We always carry a spare now so we are not at the mercy of the tire service guys who will charge you any price because you are up the crick without a paddle.
Dale