if the coin you buy suddenly goes down, what do you do?
panic sell or hold ??
It all depends on what is the currency; If it is one that, I have faith in it and still has a promising future, I take advantage of its lower price to buy more and double my future earnings.
I agree. Use the oportunity and buy more. Do only sell when you are really sure that coin has no future. In that case sell and try to limit the loss.