I was thinking that I wouldn't blame those guys too much because I can't remember how many intake valves I've installed without cutting the seat, but I always attributed the wearing to bad air filtration. Finally after making the same mistake over and over it dawned on me that there is no way to replace a valve without cutting the seat. No one told me that in all my reading. I mean, I might have seen it suggested, but not emphatically necessitated. Any wearing at all on the seat is not going to mesh with the new valve and all that's needed is to wear the hardness off the valve and it's gone. It's imperative to have the valve and seat at exactly the same angle. It's also important to have the contact patch in the center of the valve footprint. In light of that, I bought my own cutter. So far I've used it once, so it hasn't paid for itself yet lol. But after using it I discovered that I'd likely not trust anyone else to do the job. They could cut corners and most people wouldn't know.