I realize this answer may change with the blade type and razor, but how often do you change your blade on average. I'm currently changing blades every 3 shaves. I'm sure I could get more out of the Astras sp but I'd rather use a new blade.
What, again? I change blades after every Sunday shave. If a blade will not last a week, it is not a blade I would use.
As you already know, the correct answer is YMMV, so why do you care how many shaves other get from a blade?
I've taken a vow never to change the blade unless the performance is declining.
Turtle, seriously? What are you an engineer or an accountant?
I change to a new blade on each pass.