I have seen other threads that people do daily changes... Every other weekly etc. Well I just changed mine out yesterday with 33 hours on the clock and my neighbor looked them over and said they were still in good shape. Yes they had a few little nicks here and there but overall in great shape. He took a file to them and cleaned them up in 5 min. Balance checked them and they were all good. I had a new set that I put on so we will see how much better the new ones are compared to the ones I took off. I asked him if he felt they needed to be changed out yet and he said not really. If I had 33 hours on them he feels I could go atleast double with them if not a little bit more. This is coming from someone that is a retired Machinist so he knows what he is talking about. So unless you are hitting alot of rocks or whatever all the time a daily blade change is for sure no doubt over kill.