My tale comes from the other side. Two years after building our first house, a change of employment meant a move overseas and we decided to rent our pride & joy out. Tenants were recommended to us, a young couple with one child. He was in the RAAF. He would pay the rent and the RAAF would reimburse him.
Not long after they moved in, he asked if he could use excess bricks I had stored to build a barbecue. I had poured a concrete pad in anticipation of doing so myself, so had no objection. Over time, there were successive requests - if we bought the materials could they make some improvements. After two years, the next chance we had to look at the place, they had done so much work we gave them their bond back. When they eventually bought their own house, ours was spotless and in much better condition than when we left it. They confided that they had hoped to buy it from us.
Unfortunately, the next tenants undid most of their good work.