Your lawnmower should last a lifetime with good care and regular maintenance. Regularly check the oil's level and quality. If you have a four-stroke engine, drain the crankcase and refill it after every 25 hours of use. There should always be fresh fuel in the tank (gasoline that sits in the engine too long can become contaminated). Pay attention to engine controls, and follow your manufacturer's care manual. This includes calibrating your carburetor according to code. Keep the air filter and fuel filter clean so that your lawnmower doesn't lose power, run erratically or fail to start. Get rid of clumps of grass clippings on the lawnmower after your done mowing.