Hugely variable. I only burn about 20 gallons of gas per year. About one third of that is to avoid fuel spoiling, one third of that is for when I need longer trips, and one third when I screw up charging.

Even so, I get about 40MPG, so much better than an average vehicle.

It does sting to maintain an engine for 800 miles a year.

never thought about that, do the oil come out looking new?

I don't change my own oil anymore, but I imagine that it's just barely picked up some color-- Honda specifies synthetic and it's only a few hundred miles per change.

Pretty soon I'm going to be out of warranty and I'm going to stretch the oil change interval a bit beyond what they suggest-- 16 mos instead of a year. It just feels wasteful.