The best way to review your investment portfolio would be in sync with your financial goals. For example, if any of your goals are drawing close, a portfolio review could be used to put a structured de-risking plan in place. Similarly, if you have idle money lying in low-risk funds that will not be needed for the next 5-7 years or more, you could start an STP into an aggressive, high growth fund. Remember, a portfolio review should not be used to evaluate funds based on short term returns, as that can lead to unnecessary churning in your portfolio. Ideally, you should review your portfolio once a year or in case of a major life event that could impact your finances.