I used to see it as a balancing scale that should remain on the same position at all times. However, I believe a better mental model is to see it as ebb and flow. There are times you need to focus on work.
Transitioning between these states can happen in a forced way (circumstance), or you can slowly move towards a new area like ebb and flow.
If you try to maintain an arbitrary, exact balance at all times, you risk not moving forward on any focus area.