Maybe so. But I don't mind going the extra step to keep my engines in top running condition. I'm very OCD about maintenance. I change the oil twice a summer and use nothing but synthetic oil. I take care of my lawnmowers the same way I take care of my cars. Plus the cleaner the piston, valves, and fuel system are, the more efficient the engine runs. That's why my 22 year old Craftsman II push mower still fires up on the first pull and doesn't burn any oil. That little 3.5 Tecumseh still runs like the day it was bought...
L8R,
Matt