Gentlemen:

The number of shaves per double edge razor blade varies for me. For years I had a general rule of replacing blades after the third shave. Recently I have refined the number. After using a wide range of blades, I have settled on Feather, Super Iridium, Gillette 7 O'Clock "Sharp Edge" "yellow pack," Personna "red pack" and Derby. The number of shaves per blade is as follows:

Feather: Two shaves. The Feather blade dies after the second shave.
Super Iridium: Three shaves.
Gillette yellow: Three shaves
Personna red: Two shaves
Derby: Two shaves

What's your numbers game, gentlemen? Or do you have one?