Hi Bethrags, I am still sort of figuring it out. In the past I think I used it like 30ish min a day, but it's a little much for my eyes on the highest setting so I am using it on a lower setting for a bit longer. I honestly probably need to review with my pdoc again as I can't recall exactly what he said when we discussed it a couple of years back. I am trying to pay attention to my moods to make sure I don't get irritable. It happened once in the past a couple years ago. Has your pdoc recommended how long to use it for? I hope it helps you if you decide to use it.