Without sharpening it, about one week.
With continual sharpening with a blade-sharpener...about four months.
Blade-sharpeners for DE safety-blades, Yes. They were very common back in the old days. They came in a variety of styles. Some were semicircular sheets of metal or roughened ceramic. You scraped the blade against them in a side-to-side kinda see-saw motion, to sharpen the edges. Other sharpeners were like shot-glasses with frosted, rough glass sides. You put the blade inside the glass with the edges vertical, then rubbed it around inside the glass in a circular motion to sharpen the edge.
The one I use is a little zip-pull blade-sharpener. About the size of two matchboxes. You open it up, slip the blade inside, close it and pull on a the zip-cords. This spins the wheels inside (which the blade sits on top of) and this rubs the blade over the whetstones that close over the blade, sharpening it up.
You can find little doodads like this in antiques stores and flea-markets and they're often very cheap. I bought one and before I moved to straight shaving, it was the most money-saving shaving device I ever bought!
These sharpeners will work on all modern DE razor-blades.
Pop the blade in. Close it. Pull the strings (two or three times back and forth should be plenty). Open it. Nice and sharp.
What is the make and model of that sharpener? Where did you get it? I am having a hard time finding much of anything about sharpening safety razor blades online. Thanks for the info.
Should I not be using my safety razor everyday to reduce irritation? I'm starting to think my face must be super sensitive because I got some major razor burn today and didn't do anything different than yesterday. Am I "overshaving"? I don't like feeling any stubble whatsoever when I get done.
Also I have a couple other questions and didn't want to start a new thread. Should I make sure my soap is not sitting in any excess water when I'm done with it? And has anybody here ever used shave secret shaving oil? I just bought some today and rubbed it on my face to see if it helps with the razor burn and it seems to be. It says on the bottle to just it alone when shaving but I don't think that sounds like a good idea considering how tender my face is today.