Really depends on the environment the knife spends the most time in I would say. Also, depends on what you are cutting and how quick one is to clean the blade off. I have a slight patina on the belly part of the knife. I haven't been able to take a decent picture of it though. It turned a slight bronze (hardly noticeable unnless you look for it).
Some say soaking the blade in warm red wine vinegar for a few minutes will provide a dull patina. Personally, I like my knives shiny, if they become not so shiny, I'd rather it be due to use rather than forced.