I have been using a shavette for about 6 months I find that I change my blades after every use. I have used Derby and Feather blades (red holder). I see the same as posted above with the Derby blades, after the first pass I start feeling a slight tug. The feather blades I prefer to change after one shave, but I get multiple passes. The big thing I found was angle affected the level of irritation for me, I use no pressure. If you have any "obstructions" on your face like a mole... make sure to flatten the blade so you don't cut it off.