Blind people must save a lot on electricity.
They do actually!
I had a blind professor, last semester, and I swung through his office to make up an exam. It was a while before I knew he was in there because he was sitting with the lights off. I finally went in, apologized, and took the exam by the light of a nearby window (which was fine). Forty-five minutes into dead silence he panicked and yelled in this booming voiced, “WAIT, YOU CAN SEE!!!” before diving across his desk to turn on the lights. I’m sure he was embarrassed but I thought it was endearing and it highlighted a large aspect of disabled life that I hadn’t previously considered.