I have leant bikes out to people over the years, mainly when we were going biking to the same place, one friend had a spoke in the rear wheel fail on her, just a random thing when she was riding along a path, removed the spoke and joked to go easy on it.
My two bikes aren't high value but are hard to replace,
The inbred was built from parts, many scrounged off other bikes, it's kind of an evolution of a Specialized hardrock bought in 2003, the frame of which was bent in 2006
The road bike was my dad's having been un-lovingly restored (it looks like crap) by myself
no one else rides them, more because I'm fussy about things being in the right place, meanwhile I ride the wife's bikes if the mood suits, I bought her mountain bike and built her road bike so she doesn't get much say (or seem to care about the fact)