To be honest I can see my self getting up to 20 shaves from GEM PTFE, but that's a thick and sturdy blade and when it gets dull it don't bend or tries to chatter like DE blades when they get dull. The only way I can think of using a dull DE blade without getting irritation is to drop down on the aggresivness, I shave with super aggressive razors and dull blade + aggressive razor = blade bending even when trying to do shorter strokes than usual. The only way I can prolong DE razors life is to step down in razor aggressiveness so I can buff troubled spots more freely. To be honest blades are so damn cheap that even the most expensive DE if used only 3 times its still dirt cheap, I mean really dirt cheap LOL. that's why I love DE and SE shavingIt's a question of challenging yourself and your preconceived notions of what's possible. Taking small steps in a planned direction. Nobody does this 'out of the blue' so to speak. I have been actively bettering my shaves for well on to the 11th year now - I started DE shaving (mindlessly) in 1980...
It's like getting to the top of Mount Everest (or to Carnegie Hall). It takes practice, lots of practice!