I spoke to a granite supplier (Marva in MD and VA), and they wanted $300 to change a polished slab to leathered. My fabricator wanted me to sign a waiver. I was considering changing my black perimeter granite from polished to leathered, but I chickened out and am going with polished. I think enhancer would have prevented stains, but maintenance-free is better in my situation. (I'm bad at keeping up with household chores, and I have small children.)

Here is a link that might be useful: discussion: enhancer for honed granite

Thanks for the reply, nikit! Is it more common that the supplier -- rather than the fabricator -- would do the actual honing? I guess I just assumed that it would be the fabricator who would hone the stone.

You're welcome! I think you're correct -- the fabricator usually does any changes in finish. The granite supplier I mentioned was the only one I encountered who was willing to change the finish of a slab. It's worth asking, I think. (Also, in my case, my fabricator wanted nothing to do with honing a slab.)

BTW, I had trouble keeping straight the different matte finishes, but it may be worth figuring out if a matte finish other than honed could also be an option. In my area I saw mostly leathered (antique)finishes, and I was told they are a little more forgiving than honed when it comes to showing fingerprints, dust, and water spots.

Here is a link that might be useful: thread on matte countertops