I have a medium-sized lawn, but my mower gets infinite mpg. In fact, it doesn't use a bit of electricity generated by burning fossil fuels, either. The only energy source utilized by my mower is calories within my own body - I have a reel mower, and I just push it around my yard (which is no harder than pushing around a non-self-propelled gas lawnmower). No engine or motor whatsoever. It works amazingly well, and despite its reputation, doesn't have a tough time at all with taller grass. I have a Craftsman Quiet Cut, and it has been good to me - I supplement it with an electric trimmer for weeds and edging. My next door neighbor can keep his unnecessarily huge riding mower. We have the same size lawn; I don't understand why he needs that thing. It won't even fit in the back of his ginormous Chevy Avalanche (which doesn't have a very big bed). Push-reel mowers rule!