I usually get about 6 shaves out of a standard Feather DE blade. From a Feather Professional blade I usually get somewhere around 25 shaves to maybe 30 shaves before noticing any degradation in shave quality. About the same experience from the Feather Pro Style Kia blades as well. I'm not trying to squeeze every last shave out of the blade but if I'm getting great shaves then why bother changing it. First sign of a poor pass and the blade is binned be it shave 3 or shave 23.
I do take a part my razors after every shave and dry them after every shave, which includes patting the blade dry as well. So no rust issues here. If you're opposed to this then taking the razor apart then a dip in alcohol followed by a quick shake will displace the water and allow the razor to dry without getting rust on the blade.
I do take a part my razors after every shave and dry them after every shave, which includes patting the blade dry as well. So no rust issues here. If you're opposed to this then taking the razor apart then a dip in alcohol followed by a quick shake will displace the water and allow the razor to dry without getting rust on the blade.