When Have You Taken a Hone as Far As you Can?

How do you know when you taken a hone as far as you can?

Hard to say, some hones takes a lot of use to learn.
That's why I don't care much for people trying a hone once and say it's useless.
Not all hones are for finishing razors tho, far from it.
If you find a hone not doing what it should be able to, let someone else try it.
I've bought many "bad" hones that turned out to be very good once I learned how how to handle them.

The more experience you get the more you will see and feel when the edge is done on a stone. You watch the water displacement and look for the scratch patterns from the prior hone to be gone. Its a feel and visual thing. Not one but both.

When it's job is done.

Experience teaches you that.

If your just starting into this you should follow the pyramid method and watch the vids till your eyes bleed.Then you will find what works for you. I got into the habit of using the thumb pad test from the beginning. I am constantly checking that way. Now this had it's own learning curve for me but I have come to get a feel for it and also my hones. It's a skill set you earn by practicing. I also use the shaving arm at 1k and tree top method when I know I am getting close to the end on the fine hone. Once again all these things are learned as you go and you must be confident in what you decide to use!