I don't anymore, because it hurts my eyes. Hour maybe, go for a walk, do another hour... Hopefully my eyes clear up once I get a break. Treat your body well,

I don't anymore, because it hurts my eyes. Hour maybe, go for a walk, do another hour... Hopefully my eyes clear up once I get a break. Treat your body well, don't waste it making someone else rich. Besides, most of the time spent solving engineering problems is spent thinking. You don't need to do that at the keyboard.