John and Miesha are 60 years old they have $600,000 invested and need $1.2 million in their retirement account at 65 years old to be able to confidently retire. In order to do this, they need to earn 14.86% annually for 5 years and must hold a relatively high proportion of their portfolio in risky investments. How often do you suggest they rebalance their portfolio? Why is it important for them to rebalance?