Blade sharpening is important especially in the finished cut. I try to sharpen my blades at the end of each day... if not every two days. If you let them get real dull than you have to take more off. Sharp blades are great as well when the grass is wet. And of course you can tell after the lawn has been cut if the blades are dull or sharp. I think its a good practice and as well good to tell your customers that you do that.