Backtesting is necessary to test trading strategies based on historical data to assess whether we are good enough at analyzing or whether further adjustments are needed. traders who are lazy to do backtesting will usually have difficulty using certain strategies in their trading because they lack data to optimize their trading.

However, backtesting cannot guarantee that a trader will be successful in their trading. because it could be that the strategy can work very well on historical data but fail in the real market. but that is much better than traders who only trade based on their luck.