Mock tests play a vital role in UPSC exam preparation by providing a realistic assessment of a candidate's readiness. They simulate the pressure of the actual exam environment, helping candidates manage stress and time effectively. Frequent practice through mock tests allows candidates to identify their strengths and weaknesses, guiding their study efforts. Additionally, thorough post-test reviews enable aspirants to understand mistakes and refine their strategies, ultimately enhancing performance during the exam. Thus, incorporating mock tests into preparation is essential for success.