Helico's got a real good point, but I sure am tired of replacing $20+ blades because I ground off a few millimeters getting too close to the house (brick), the deck (pt pine), a tree,,,, Replacing $2-$3 dollar blade grips, feathering spindles, or bent links and such, sound a whole lot better to me than replacing $20 main blades right and left. But then, I admit it! I can fly, it's just not controlled flight.