There are several warning signs that indicate your lawn mower's blades need sharpening, including uneven lawn cuts, torn clippings, and uncut areas. A dull blade on your lawn mower is not only inefficient; it can also be detrimental to the health of your yard. The clean cuts of a sharpened blade also allow your mower to work more efficiently without as much unnecessary work for the engine. To decide when to sharpen versus when to replace your lawn mower blades, consider whether you can see visible, irreversible degradation (like cracks) in the blade. Remember, if your mower blades just need sharpening, keep up this task a few times a year to avoid replacing them too early.