Cylinder head milling

I have never milled the china wall on the intake or block.
Me neither- that's a big whompin' gap at the china wall/manifold that usually gets sealed by a cork or foam gasket, or a big fat old bead of RTV. Any shop that tells you that you need to mill one of those surfaces is just trying to make a couple extra bucks off of you. Does anybody seriously think a .028-.084 cut off the manifold bottom or the china wall amounts to a hill of beans when you've already got a quarter inch gap with a foam seal?