I get 20 from a Feather Pro. I'm trying the soft guard at the moment and it's at 10 at the moment and still ok. If it does the 20 then it will be 6 pence a shave. More than DE but I prefer SE anyway. If you bulk buy its a bit cheaper too.
I still use no other blade. Conventional guard blades I always found mild enough but simply not effective. These chaps are mild as a mild thing but still remove the whiskers.
I really don't care what they were originally designed for!