Without a doubt this is good advice, I will also say that having a defined level in which you will not tolerate more losses and cut them, also known as a stop loss, is very important if you plan to make money for the long term on this market, and the reason for this is simple, many traders do not like to admit they did anything wrong and when they are facing some losses instead of closing their trade they keep it open expecting for a reversal, and when it happens and they avoid losing a small amount of money they are happy about it, but eventually they will find out that the market does not always makes a reversal and instead of the price plummets, and that is when they lose a massive amount of money.