Probably if you use the same razor every day you don't need to use oil however, consider that carbon steel has a real affinity to oxygen and that spells rust. I would be willing to bet that if you dried a razor off and left it out overnight in the morning if you put it under a very high power microscope like an SEM you would see rust and corrosion on the very edge. It forms very rapidly. I oil all of mine with Sterol.