Thinking is an art,
and has a technique,
like every art.
The previous exercises were aimed at the separate development of soul qualities: control of thought and willing, equanimity with respect to feelings of love and sorrow, positivity in assessing the world and open-mindedness towards life. This exercise is designed to ensure harmony between these qualities.
Some have a strong tendency to think, others have developed their feelings better, again others live strongly in action. Through practicing the five exercises together and according to need, harmony will be created between the three faculties of the soul. You can practice combinations of exercises for a while, but you can also choose a specific exercise that you need in a certain phase in your life.
Perhaps it gets too much after a while. Then it may help to think that someone who practices, learns and grows, and someone who does'nt does not. The exercises get easier because you have practiced them separately at first; you can do them to some extent. You have already gathered experience, acquired skills and built forces that will make it easier to continue. You've already become more attentive to your soul, you improved on your weaknesses and limitations and you already react more balanced than before. By going through this exercise you will improve this further.
After you've done all the exercises once, you can stop for a while and then start again or just do the exercises that did not go well. In this way the basic exercises can be a help to develop yourself continually.