Not much, particularly with the knives from those links. I don't really do anything for mine other than dry them right after use and wash them right after cutting something like lemon or onion. I'll occasionally use some barkeeper's friend to shine them up, usually when I sharpen them, and then give them some oil. That's about it. There's no rust, not even much patina after a year of daily use. The first carbon steel knife I had was more sensitive, it got discolored in just a few minutes after cutting an onion, but bk's friend easily removed that.