Mock tests are crucial in the preparation strategy for UPSC aspirants as they simulate the real exam environment, assisting candidates in managing time and stress effectively. They provide an opportunity to identify strengths and weaknesses, allowing for targeted study. Engaging in frequent mock tests helps in familiarizing oneself with various question formats, enhancing problem-solving speed. Additionally, detailed analysis of performance helps in understanding mistakes and refining exam techniques, ultimately leading to increased confidence on exam day.