The frequency at which you should use the Portfolio optimizer depends on your investment strategy and the market conditions.
Investors who are active and want to make the most out of changes in market conditions should consider optimising once a week or bi-weekly. While investors who are not very active can consider reviewing and optimizing their portfolios on a quarterly basis, or whenever there are significant changes in their investment goals or risk tolerance.
Note that optimising does not necessarily mean the investor may require to rebalance their portfolios. If the new optimum quantities suggested by the Portfolio optimiser does not show a significant benefit in the equity curve compared to current holdings then they can continue without rebalancing.
Since market conditions and performance of individual stocks can change over time, it is important to regularly reassess your portfolio and adjust allocation accordingly. The portfolio optimizer is a very simple and yet powerful tool to identify the right instruments to invest in and determine their optimum allocations.