It's recommended for all oil changes. If you look around there are other oils containing zinc that are designed for use in motorcycles which should work as good as the Kawasaki branded oil so long as they have similar zinc content. Depending on how much dust you kick up you might consider getting a Donaldson style 2 stage air filter, there's a number of places on the internet where you can get one. These are typically found on the commercial Kawasaki twins and can be easily adapted to work on residential mowers. They provide a significant improvement in air filtration and due to the size they aren't restrictive to the point that you'd need to re-tune the engine. I put one on my Big Box store Cub Cadet XT1 50 which has a 23 HP Kawasaki FR691 because of all the dust that gets kicked up here in Oklahoma. It's about 4 years old now with no issues mowing an acre about every 4-7 days with normal maintenance. Pulled and checked spindles recently, still plenty of grease in the sealed bearings, no zerks. The spindles are MTD with chinesium bearings. Will replace them with Timkens if they ever go bad.