If your push lawn mower is not working as well as it used to work, you might be thinking about replacing it. Before you purchase a new push lawn mower, check your current mower's blade. Over time, lawn mower blades grow dull and no longer cut grass as effectively. If you take your lawn mower blade to a hardware store that offers a blade sharpening service, you can usually get the blade resharpened for a small fee. With a newly sharpened blade, your old lawn mower could be working just like new.