Scientists discard a model when?

Scientists discard a model when it consistently fails to accurately predict or explain observations and experimental results. If new evidence emerges that contradicts the model's predictions, or if it cannot accommodate new data or phenomena, it is often deemed inadequate. Additionally, if a more comprehensive or simpler model is developed that better explains the same phenomena, the original model may be replaced. Ultimately, the goal is to ensure that scientific models remain reliable and useful for understanding the natural world.