This is my first winter using light therapy and while it has really helped my mood, I have found figuring out the optimal amount of time using it to be tricky to figure out. If I use it too much I have insomnia, if I cut back too much I get down and kinda crazy. The days are getting longer and I'd like to slowly wean off of using it. I'm wondering how veterans of light therapy go about decreasing time? In terms of minutes? Or a few seconds a day?