LB18 first off ignore this user, he does not have a clue what he says and only follows around a mod kissing his butt. Okay wow you like to sharpen which is good, however I think you went a little hog wild there with the grinder. LOL Now you are using the wrong type of wheel to sharpen your blade you need a flapper type wheel with 40 or 60 grit, then be careful to try and maintain your pitch on your blade while sharpening of 30 degrees. Grass, dirt, sand, leaves, sticks, it is all hard on blades and metal is just metal so don't feel too bad or worry about how it is wearing or deteriorating, it would take 2.5 or 3 of your blades to make one of mine and my blades are not as wide as they were when I started mowing this season because I constantly check them and hit them with the flapper wheel every week maintaining their edge, but when you mow 12 plus acres per week your are into a some grass. But to answer the main question; I personally would not have allowed my blades to wear that much before replacement, but each is their own.
