Change the blades on your lawn mower with the Arnold 54 in. Mower Blades for John Deere to ensure a healthy-looking and clean-cut lawn. Mowing with dull blades can tear and rip grass tips, leaving the lawn susceptible to disease and browning. This replacement mower set blade cuts grass cleanly and makes its way through grass more efficiently, reducing overall mowing time and effort. For the best results, blades should be replaced at least once every year.