When I was a very young man, no more than about 18, I was taught a lesson about this.
I had got in the habit of borrowing things from my neighbor across the street, and I was not as careful as I should have been with them. So one day I called him up - "Allen, can I borrow your thus-and-so?" "Well, no. You can't." I was not expecting this response, and I asked exactly the question he was waiting for: "Why not?" "Because every time I lend you something it comes back in bad shape. You blunted my drill bits, you bent my floor jack, and I don't think I ever got my hacksaw back at all. The things you don't break or lose come back covered with dirt and grease. So no, you can't borrow it, or anything else. Don't ask again." I stammered out some apology and we hung up.
He was absolutely right, too. I'd been completely inconsiderate. I was deeply embarrassed and resolved to change. From then on I never borrowed anything from anyone unless I could return it in good shape and maybe cleaner than when I took it. Mostly I stopped borrowing completely and bought my own stuff, and learned to take good care of it. Decades later I tracked him down, called him, and thanked him for the life lesson.
The one time in my later life that I lent a significant quantity of tools to anyone, it was to my then-girlfriend's son-in-law to do some remodeling on her house. A lot of the stuff got trashed and some of it got "lost," and I was reminded of being that guy all those years ago. Fortunately most people I know have their own tools and don't need to borrow mine, so I'm not in that position often.
