I know what you are thinking... "you are crazy!!" Yes, I know most people go only 2-4 days with a Feather before claiming that it is dull. But I had to test the blade for myself. I got my inspiration from Treedoc 34 Shaves with one Gillette Swede blade. I guess I am truly from the show me state.
Most of the shaves I did only 2 passes and 3 passes on the 4 weekend days. I used a Merkur HD and Tabac soap for lathering right after the shower. No preshave oil, glycerin, olive oil. The first 5 days went great and shave just BBS-fine. On the 6th day I notice a small difference, however that was probably due to rushing my shave. This prompt me to use a Derby blade on half my face and the same Feather on the other half on day 7. Quickly concluded that the Feather was still as good as the Derby on day 7 so I went on. The rest of days 8 to 14 were good as well. However, I decided to pull the plug on the experiment and move on. I wonder if the Feather wears out more on a Slant leading to less shave days. Unfortunately, I don't think I will push a Feather-Slant combo past 7 days.
I only have a 3 months of DE wetshaving so I am still experimenting. With the sampler pack I got, looks like I will be experimenting for another year. What did I get out of this? Well, your obvious YMMV, but also that its very hard for a new guy to tell the big differences from 20 different blade types out there. As soon as I finish trying all of them, I am going to have to start over. I also determine that I can reasonably use a blade for 7 days before rotating. The blade might still have some edge/sharpness to it but I will not push it until it starts to get dull and therefore get better shaves out of the blades. The 7th day rotation is what many people do already, unless you are one of the 2-day blade group.
Most of the shaves I did only 2 passes and 3 passes on the 4 weekend days. I used a Merkur HD and Tabac soap for lathering right after the shower. No preshave oil, glycerin, olive oil. The first 5 days went great and shave just BBS-fine. On the 6th day I notice a small difference, however that was probably due to rushing my shave. This prompt me to use a Derby blade on half my face and the same Feather on the other half on day 7. Quickly concluded that the Feather was still as good as the Derby on day 7 so I went on. The rest of days 8 to 14 were good as well. However, I decided to pull the plug on the experiment and move on. I wonder if the Feather wears out more on a Slant leading to less shave days. Unfortunately, I don't think I will push a Feather-Slant combo past 7 days.
I only have a 3 months of DE wetshaving so I am still experimenting. With the sampler pack I got, looks like I will be experimenting for another year. What did I get out of this? Well, your obvious YMMV, but also that its very hard for a new guy to tell the big differences from 20 different blade types out there. As soon as I finish trying all of them, I am going to have to start over. I also determine that I can reasonably use a blade for 7 days before rotating. The blade might still have some edge/sharpness to it but I will not push it until it starts to get dull and therefore get better shaves out of the blades. The 7th day rotation is what many people do already, unless you are one of the 2-day blade group.