I dont know how you could go 90 hours with only 4 sharpenings, and have the blades shot already. That seems like they are going out quick. I sharpen, often to keep them very sharp, but dont take off much, so they still last very long for me.[/QUOTE]
i meant all 4 prior sets were sharpened about 4 times , so in the 350 hours, i've put on 16 sets of sharp blades (just estimating), 20 something hours before sharpening.