Good post goforchrome! Lactic acid is a killer of exhausted fish which have been played too long, and there is nothing more gut wrenching than releasing a fish that you had no intention of harming only to have it go belly up because it was played too long.

My personal gauge is that, if the fish isn't gaining on me, then I'm gaining on it.....if it sits and sulks, the rod or line is too light.

Happy Fishing