We have operated our rig for 13 years and 70K miles with three breakdowns that required towing. It is approaching its 20th anniversary of in service date.
If I were less slow on the uptake, one would have not cost more than an hour of time lost. Another cost one day waiting on a fuel line replacement.
The only major failure was the fuel injection pump which did interrupt things for a bit longer.
I have repaired things in the campground but none caused more than a few unmentionable utterances due to inconvenience.