I use a die. I have a 12 razor rotation and on every pass through the array I rotate the die. After 3 shaves I replace the DE blades and after 6 I replace the Schick injectors.
Got this 20 sided dice to keep track of my SE blade uses as I rotate it with my blackbird also. Seems like a neat idea that I got from here. All black die looks nice
Since somebody revived this thread nearly two years after my original post, I thought I'd post a follow-up. The picture below shows my current rotation of razors, each with a die at the base. Generally when I get to 6, I change the blade. I don't remove blades between shaves. Sometimes, particularly with the AC blades, I'll continue past 6 until the blade starts feeling rough.