Long-term strategies for candidates to retain information for the UPSC exam include regularly revisiting notes, implementing spaced repetition techniques, and engaging in active recall methods. Breaking down material into manageable chunks promotes better absorption and understanding. Utilizing visual aids such as mind maps and charts can help in creating connections between concepts, enhancing memory. Regular self-quizzing and group discussions reinforce learning and encourage deeper engagement with topics. Establishing a well-structured revision schedule that revisits topics periodically ensures that candidates stay familiar with all subjects, aiding in long-term retention for the exam.