The resting times between your focused-mode efforts should be long enough to get your conscious mind completely off the problem you’re working on. Usually a few hours is long enough for the diffuse mode to make significant progress but not so long that its insights fade away before being passed on to the focused mode. A good rule of thumb, when you are first learning new concepts, is not to let things go untouched for longer than a day.
Great advice for students. A short break is okay, but probably not more than a day.
