I can get a couple of weeks out of a decent razor blade system. It starts going doing hill after a week or so, but they don’t rip my face off.
I don’t shave any ore. Just use c,ippers to,keep the beard part cropped, and let the mustache grow a bit. Haven’t shaved In Years actually. But I don’t work so the scruff look is fine for me. Back,when I did shave though, the 2 blade ones woild last me about 1 week as I never used shaving cream - just dry shaved every morning. They would have lasted longer with shaving soap.