The thing I look for is uneven hone wear. Could be from a poorly ground blade but more likely from improper, heavy handed, honing. An example being where the point end is much narrower in width than the heel and the point end of the spine shows much more wear than the middle or the heel end. Then there is the 'frown' where the edge is beginning to take on a U shape and generally the excessive spine wear is more in the center and out both ways. You couldn't give me one of those for free.