The tines sharpen themselves, more or less, so I don't have to. The wear occurs between the cutting edge and the outside edge - hard to explain in words. I have a couple spare tines in the garage & I'll take a photo of fresh and worn tines and post them this weekend so you can see what I mean. It hasn't affected performance, but I'm aware that they're wearing and know that I'll probably have to replace them before the tiller itself wears out - which is what I would expect from a well engineered product - the wear component wears out sooner that the rest of the machine and is easily (aside from cost) replaced. In ground engaging equipment I consider what ever part actually does the work on the soil to be a consumable. The tines work the soil and are getting consumed, as it should be.