A while ago, I noticed that 1 pass with a straight and 1 with a DE give me a better shave than 2-3 passes with a straight. After a bit of thinking, I worked up a hypothesis, that I finally got to test today.
The hypothesis is that even a single pass beats up a blade enough to adversely affect the shaving performance.
I started with a week's worth of stubble (was waiting for the irritation to go down after testing some new DE blades). So I stropped up 2 Americans -- Chandler 9/8" custom and the 9/16" Genco Grant.
After I mowed down the worst of the stubble with the Chandler custom, I did the cleanup pass with my Genco.
The shave was very comfortable and as close as anything I've ever got.
Conclusions:
1) Strop up 2 blades before hitting the shower, to avoid interrupting the shave with another round of stropping.
2) If you can't afford 2 shave-ready blades, you can always restrop between passes.