Hello, I am fairly new to this but have been using the money geek model portfolios to help with my TFSA investing. I have a question about timing for buying/selling and making changes to a portfolio. I know the general rule of "buy low-sell high", but is there any other guidance that you can provide on when is the optimal time/frequency to rebalance or add funds to a portfolio (and should you still do it if the value of some of the ETFs is considerably higher than when you originally bought them, e.g. close to a 52 week high). I've encountered situations where I sold some stocks and had a fair amount of cash sitting in my TFSA, but I've hesitated from re-investing as per the model portfolio breakdowns given the significant increase in value of some of the ETFs. Is that just a beginner's hangup? Any insight would be much appreciated. Thanks very much for all the work you put into this blog!