I think it depends on how much profit we want but don't too greedy because we can lose our profit if we are expecting for a big profit and we don't know if the price will stay at that price or getting a decrease in the next minutes. so if we think that it's enough for us to take the profit then we need to sell it before it's too late for us. but if we don't want to take the profit right now and we only want to sell in the next month then we don't have to do anything and only check the price.
It is important that before buying the coin, we already know when to take profit because whatever happens, we know what to do. This is one of the major mistakes of some traders and I am guilty of this too before because I tend to become greedy as I don't know when to take profit so I am always hoping that the price would go up only to see it the next minute drop down in value and then regret why I didn't take profit when the price is high. I still need to get over about the control of emotion as it is what hinders me to think properly. My recommendation would be to take profit from time to time and do not be greedy.
Giving advice is a thankless job, but I'm still gonna take the risk. It is necessary to distinguish short-term trading from long-term investment. In the first case, it is really important to understand when you need to close the position. In the second case - either just hold, or buy each month additional coins for a certain amount.
If you are in for the long term investment then a good way be cost averaging so that you will not have a big loss when the price goes down in value. Besides that, the short term price wouldn't matter that much to you as you are positive that you will reap your profits after a few years.