If I can touch the edge without requiring stitches it's too dull. If the blade can't split a log in two with nothing but the weight of the blade. It's too dull. If I waive it through the air without nuclear fission happening, it's too dull. I can drop it on the floor without tearinf a hole in the fabric of the universe, it's too dull. Unfortunately, all of my knives are dull.