I also do not lend my tools to anyone except my dad. As a few others have said, it is my dad who taught me not only how to use tools, but how to CLEAN them and sharpen them when the job is done so they would be read to use the next time they are needed.
I made the mistake of lending my father-in-law my good tree loppers, at my wife's request, because he said his did not cut very well. And now I know why.
When he eventually gave them back, they were all rusted up, and the blade had actual chunks taken out of them, like he tried to cut stones with them or something! How that happened, I don't know, but apparently he also had left them out in the yard for along time through several rain storms. The only reason he even found them to give them back was because he hit them with his lawn mower.
I showed this to my wife, and she said she was sorry, and that her dad was not good with tools, and he never learned from his dad how to properly take care of things. I was pissed, and I had to buy a new set because these were destroyed beyond repair. And the worst part was he NEVER said he was sorry, or that he would replace them, or anything!
My dad told me that if you lend a tool to someone, NEVER expect it to come back in the same condition it was in when you gave it to them. He said most people who borrow tools have no real clue how to use them properly, nor will they ever clean them up after use. And if you do actually get them back, be prepared to clean/sharpen/fix/replace them.
To this day, I threaten to say something to my FIL about this, and my wife will go ballistic! I love to watch the little veins popping out of her forehead.....
Jim