Some of mine are common sense but often overlooked. I run Premium fuel in my air cooled engines because they run cooler so they last longer. Make sure all grease zurts get greased often. Check and grease wheel bearings because they where, loosen, and burn off grease. In 2 cycles you can change spark plug #s to run hotter or cooler. On machines I'm not using on regular basis I loosen the belt tension and apply some belt dressing so they last longer and don't break in half when I'm using it. Keep gas cans out Sun so the gas doesn't loose its octane. Check wheels for straitness and free movement(sounds stupid, but can cause more where on equipment and you if its not right.) I have more but I'm someone else can touch on good ones as well.