Stropping before each shave will help maintain the blade's original sharpness but only if your stropping technique is good and even then not forever. I don't use any tests but just go by when I think a razor does not shave as well as it should. At that point I will try a few laps on a pasted balsa stop and do a shave. If that doesn't work it goes back to a finisher like the Nani 12K. If it still doesn't shave well enough I go back one step in the honing progression and so on till it does shave up to snuff. That is just how I do it and everyone has a different maintenance routine.

There are quite a few different techniques that have to be learned and refined when shaving with a straight that go into making up a good shave. How well you can hone, strop, lather and actually use a straight. Any one or combination of them done sub par can lead to a poor shave and an edge not keeping it's sharpness long. It is a bit complicated and frustrating to sort it all out. You are right too that it is one of the reasons safety razors were so well accepted.

I have been at this coming up on the 1 year mark and just fairly recently have all the bits started to really come together. I still have enough failures too, just call me a slow learner. I don't know if that helps any but just saying it takes time to get good at the many different aspects of maintaining an edge.

Bob