Ok, my lagers? I've had them stop bubbling in as few as 4 days. 5 is more usual. A long time ago I was in the 10 days 2 weeks length of time.Lots of healthy yeast, O2, nutrients in the boil shortened the time.
In the absence of a flow meter, aim for just enough flow that you can perhaps hear some bubbling and see a small disturbance of the surface.