My process is to let it run until the bubbles are no longer seen rising to the top. Then it is turn off and the flasks put in the fridge to flocc out for a day or 2 before brewday. Decant off most of the liquid, swirl to suspend the yeast and pitch. You can also add some of the fresh wort, swirl, and pitch.
How long it takes is hard to give a number of X for. It depends on the starter size, the yeast pitch rate and health, yeast strain, and room temperature you have the starter in to name a few things.