As others have said, some blades I've used seem to last longer than others. Some like a Feather, which is really like, are best with fewer shaves. I'm still trying to identify the amount of shaves that can be used with a blade. But I think this is very subjective and hard to pinpoint. As there are too many variables involved. For example, sometimes I use a blade to shave every day. Other times I may wait more days to shave. Therefore, the blade might not be as slick the first pass. In my experience, you can generally tell right after a few strokes if the blade needs to be replaced.