After driving the last 300 miles home on one trip, I checked the tire pressures the next day. One inside rear registered "0". I limped to my RV dealer. They checked both RR tires and found a large nail in that tire. I may have picked it up as I was pulling into my building or anyplace else on that last leg. I drove slowly up to my dealer, about 3 miles away and had them replace both tires. Even the good one could have been carrying the entire load for some part of the last leg. Then I had them install a TPMS monitoring system with a remote panel on the dash.
I may have another instance like that some day, but now I carry a mounted, aired up spare. I made room for it by removing the entire set of Metric tools I was carrying. :)