If you don't mind how it looks at first there is no reason that grass clippings can not be left on your lawn. Grass clipping should be as small as possible which is easily achieved when your lawn is mowed regularly. The clipping should be able to break down easily and deteriorate - so longer grass clippings should be avoided. Clippings are a perfect source of nutrients and rich in nitrogen. Feeding your lawn with recycled grass clippings mixed with a lawn fertilizer provides a very healthy and cost effective method for improving the quality and appearance of your lawn.