For those of you using a hand-held device,
How long and from what distance (to your face) do you use your hand-held device?

I am currently using a Red Light Man (red lamp 670 nm). I use it once a day for 30-50 seconds per area from a distance of 15 cm. Are there people who are actually capable of using it (this one or a smilira device) for more than 3 minutes? If so, what is the distance of the lamp from your face?