You can determine whether a principle is effective for your personal growth and character if you find meaning or a certain level of success in your actions. You should be able to say that you are the person you are today, because of actions and choices you made in the past. Try to assess and list down turning points in your life wherein you had to make a major decision that led you to develop new abilities, morals and virtues on how to become a better you.
Consider how the choice you made in the past turned you into a completely new person. If you feel regret or would want to change things if you only could, then you may not find that certain virtue helpful. However, if you realize that you have become stronger because of a hard choice in the past, then you will find that the trait is needed to complete your good character.
It is must that we bring about some conceptual changes in our life as there is always a space for them.