The Ideal situation is to set your lawn mower so you get small grass clippings left on the ground after mowing. These small clippings are called mulch. You want to cut approximately 1 inch of grass each time you mow to prevent larger clumping from suffocating the soil and grass. How often you cut your lawn depends on how fast it grows an inch. During peak season this can be every week and during fall this could be every 2 weeks depending on climate and weather.