The majority of mowers come with a top set which allows you to cut at a height between 3.25 and 4.25 inches. This setting is best for your lawn. At 4 inches, however, some turf blades might be "laying-over". Some prefer to mow at 3 or 3.5 inches. Lawns that are mowed at 3.5 to 4 inches look great, outcompete weeds, and can tolerate grubs.