Most traders have the tendency to take positions and exit positions with the same amount (i.e. trade “all in” and “all out”).
However, this is not logical because the market does not always have a clear direction up or down. Sometimes, the market is moving within a range, or a current move is close to an end. The markets are also sometimes affected by highly unpredictable key and important news. It is thus prudent to adjust trade amounts in accordance with risk. If the market picture is not clear, then it is prudent to trade both slower and less. You can subsequently increase your position if the move goes in your direction.