Good points. I've tried several blades over the years and still have a few good options on hand. However, my best and most enjoyable shaves with DE razors have come from Feather blades. I will try some other blades to see if I can extend longevity. I used to like Derby and Astra blades, and IIRC got more than two shaves from them, which likely speaks to your point about a not-so-sharp blade lasting longer. Eventually, I settled on Feather as my best shave and then purchased them in bulk at a fair price that got me years of shaving from that supply. The most I ever shave is every other day, but usually, every three days. Now that I also use SE Artist Club blades that give me 10-12 shaves per blade, my annual blade consumption is so low I don't think too much about longevity.After shifting to wetter and slicker lather I found that my blade longevity increased by up to 50%. This won't take you from 2 to 25 but may help. Blade sharpness is also a factor. The sharpest blades, with the narrowest cutting edge angle like the Feather blades you use, don't tend to provide as many shaves as other blades. Many B&Bers only realize a couple of shaves from Feather blades. Again you need to look at this in light of your beard characteristics, if you need a really sharp blade for a good shave changing blades might not be the best option.