This has been a great thread/discussion, and really got me thinking.
I just moved from a subdivision near Detroit to the country in Ohio. When living in the subdivision, I had one neighbor that operated just as I do, return it ASAP in the same or better condition. We would borrow tools all the time, our running joke was between the 2 of us we had every tool needed for any project covered!
On one occasion, I used a few (size specific) drill bits of his for some tough drilling, and broke both of them....immediately ran down to Ace and purchased 4 bits, 2 for myself and 2 new ones (higher quality) for him.
On another occasion he borrowed my edger and noticed the oil a bit dirty, so changed the oil for me and filled it with gas.
Conversely, another neighbor still has my hedge trimmer that he borrowed a year ago. (And I'm 250 miles away now) He would borrow items that I would forget about, and when he would eventually bring them back, I'd say, "oh, so that's where it was".
Now, living where I am living, I'm able to use all my tractors & equipment. I have one brother-in-law that wanted to use a tractor for "about a week" to do some various chores around his house, in exchange for storing it in his pole barn.....I ended up putting it in storage.
The other BIL has requested the keys to my excavator sitting on our property.....and I just can't do it.
Now I like these guys and get along very well with them, but what one poster mentioned about the insurance company coming after YOU to recover medical costs if something were to happen...that keeps sticking out in my head. And, what if someone else blows a final drive out of the excavator while I'm gone....can he afford it? (no)
What I've done is offered my tractor (and myself) to the BIL needing the tractor work done. The other BIL I went and did the job myself, clearing an area for a food plot.
SO I guess it depends on the situation, as many have said "I go with my equipment" each scenario is different. Small stuff, sure. Big stuff.....which is expensive to repair and could cause injury.....be careful!