Then each time before shaving, take your modern, high tech, double blade safety razor and stroke the blade, opposite of shaving action, across the leather a few times. This is good for men or women's razors. After years of many nicks, I have not had a nick since starting to do this. You notice the blade getting dull and not shaving as well, instead of noticing how much blood is drawn to determine a worn out blade. And the blades usually last longer.
Consistent angle seems to be the most important factor in sharpening a tool.
Latest trend is to sharpen woodworking tools with different grades of fine sandpaper on plate glass. I am careful to maintain a consistent angle in all steps. The Woodsman's Pal is one of my favorite finds for a packable trail clearing tool. See the tools section in the Knife Center link below. It has nicks in the blade but is still going strong.