Revision plays a vital role in the UPSC preparation process, serving as a way to reinforce key concepts and ensure retention of information over the long term. It allows aspirants to identify weak areas needing further focus, especially as the exam approaches. Developing a systematic revision schedule ensures that all subjects are revisited adequately, helping candidates recall information during exams. Techniques like active recall and summarizing concepts aid retention. Overall, consistent revision strengthens understanding and boosts confidence in tackling the vast syllabus.