I use knives professionally and they charge up to $20 for each knife. I have a Wusthof, a Koran, and some Mercer utility knives. It sharpened my knives like new. So much so that with regular use of my maintenance thief, I don't have to sharpen it for months! And when I sharpen them, it's only with a ceramic stone. Put it on the table, find an angle for the blade and boom! New knife.