I've had one last only a couple of weeks and another six weeks but I average a month each with these. Crucial, I believe, is that after use I thoroughly dry the blades by whooshing them through the air then applying a brief blast from a hairdryer. Changing them only once a month makes them seem quite reasonably priced. I used much cheaper Tesco triple blades for years. They lasted 2 weeks but were very cheap. Then they went cheap and nasty - the quality dropped alarmingly, so I won't be going back to them. With the Fusions I have one handle with the vibration function and I prefer using that even on the ordinary blades.