Your mind and thinking is either in focused mode or in diffuse mode. It can’t be in the two at the same time. Alternating between them is an important thing during learning. Forcing yourself to stay in the focused mode for too long won’t give you better results than when you regularly switch to the diffuse mode.
In the focused mode, your mind is fully focused on one task. Your thinking and problem solving follow familiar ways, around solutions that you might have solved before and that are stored in your memory. You are working on the details of your big picture. Staying in focused mode for too long won’t result in better results
In the diffuse mode, your mind seems to be turned off. Instead of focusing on a thing, you are doing something mindless, e.g. a simple physical tasks like cleaning or running. Your subconsciousness however will keep on working. If you are in the diffuse mode, you give yourself the possibility to access chunks that not seem to be related to what you were working on but that might help you to come up with a creative solution. In the diffuse mode, you are looking at the big picture.