Opening one trade at a time can be a viable strategy for some traders, particularly those who prefer to concentrate on one trading opportunity at a time and have a low-risk tolerance. A trader can closely monitor their position and make adjustments as needed by only having one trade open at a time, which can help to minimize losses and maximize profits.

However, it's important to remember that only opening one trade at a time can limit potential profit opportunities, especially in fast-moving markets or when there are multiple trading opportunities available. Furthermore, if a trader's only open position is losing money, they may be tempted to hold onto the position in the hope that it will eventually turn profitable, which can lead to even more losses.
Finally, whether to open a single trade or multiple trades depends on the trader's personal trading style and risk tolerance. Regardless of the number of trades open, it is critical to have a solid trading plan and risk management strategy in place.