1. How often should I sharpen my blades. I probably have about 10-12 hours per week mowing. So far this year the grass has seemed to have dulled my blades quickly. The fluctuating temps. and rain have made the grass hard to keep under control when my accounts only want their lawn done once each week. 2. How long should a blade last before I should replace it? 3. Where is the best place I can purchase blades, or should I just stick with my dealer? I just bought a new set of blades for my JD 737 about 4 weeks ago. I think for the three blades it was something like $45. Can I get quality blades somewhere else? 4. How many sets of blades should I keep on hand? Currently I have two. One is the set I used all last season.