In my world we honor those willing to share by being fair and more than fair. If you borrow a piece of equipment you return it promptly and return it in the same or better shape than you borrowed it. In the farming world, we would top off the fuel, grease and/or complete service, clean the cab/interior, pressure wash after checking with the owner on their approval. All these things are done for the appreciation and common respect we have for each other. It's why we get to borrow again. It's why we offer our own to them in a time of need. If the equipment breaks, we repair it. If we destroy the equipment, we replace it.
If you can't afford to own it, don't borrow it.