When the body is perfectly balanced the 7 Chakras give you exactly the right amount of energy in each area. In this day and age there are so many variables that could throw you off. A few examples include pollution, the environment, work, home life, spouse, kids, death, having a baby, any type of stress, sickness and so on.
Since everything in the Universe is made of energy it makes sense that the human body needs to be balanced in energy itself. The strong suggestion would be to balance your Chakras at least 4 times a year, coordinating with each different season as it changes. It’s like house keeping for your body.