There is not a moment where is better to take profits.

When you start investing you should have a strategy with a well-studied asset allocation. So with periodic rebalancing you will buy when the price goes down and sell when the price goes up, as the allocation will be unbalanced by the market performances of your coins.

Obviously it is an extreme simplification, but I advise you to start studying how to build a well-organized portfolio, otherwise it cannot be considered investment, but trading/gambling.