Heya bro! I've only used the Pro Guard blades so far, and I'm on my first blade of the pack. I only use the ACD-N on the weekends, since I have to take so much more time while I'm just learning exactly how to not cut myself to ribbons. I've used it 3 or 4 times now, and the blades are supposed to last 7 - 10 shaves. I do know that this first Pro Guard blade seems as sharp as the day I put it in. I also have pack of the Pro and a pack of the Pro Super blades, but I've not even opened those yet. Sorry I couldn't be more help, but I'm greener than the grass outside when it comes to this razor. So far, I love it -- it's awesome. Just takes me a LOOOOONG time to shave with it (which isn't a bad thing at all).