Replace the blades on your mower with the Arnold 42 in. Xtreme Mower Blade Set 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. These replacement blades are ideal for finely cutting grass clippings and redistributing them back into your lawn, providing essential nutrients. For the best results, the mower blades should be replaced at least once every year.