Briggs & Stratton claim their 675EXi engine never needs an oil change. I personally ain't buying that claim. All oil eventually degrades no matter how smooth their piston bores and cooler running their engine is. It's asinine that they do not put a bolt on the bottom to change it out so I have to tip the entire mower on it's side to drain it which means any sludge that settled to the bottom is now still in the mower when I tip it and probably won't travel out the top completely. This is planned obsolescence in design. They want you to just wear this one out instead of changing the oil.