Quote Originally Posted by Redwoood
The 'Joe' method is what I'm trying to learn right now. Again, I'm not too happy with my success rate in predicting the shaving performance of a particular blade.
Practice with a fresh single edged blade to calibrate your thumb. You'll notice that it not only grabs your thumb but you can actually feel a thin edge. That's the difference between sharp and keen, and you can feel it happen. When your last abrasive stops showing improvement you've done your best with that razor. Continuing may still give you some improvement but you'll start getting diminishing returns.

The danger of overhoning with your finest grit (assuming you go beyond 8K) is slim, but why waste your time.