I replace blades that have been beaten up by rocks and foreign objects but I don't sharpen them first. If the wear and tear is not too bad, that is when I break out my angle grinder with a 60grit flap wheel and put a 45 degree edge on the cutting side and a few steep passes on the backside. How do you guys take care of your blades? Tempted to try "new" blade designs but always keep going with regular mulching blades. Anyone have a success story on a particular blade design I should give a try?