Practice with sample papers leads to success in the UPSC examinations by providing familiarity with the exam format and types of questions encountered. Regular practice develops time management skills and helps identify weak areas for improvement. Answering sample questions allows candidates to apply theoretical knowledge, enhancing comprehension and retention of concepts. Analyzing performance on these papers can guide revision strategies and sharpen analytical and writing skills. This iterative process ultimately builds confidence and reduces anxiety, crucial for performing under pressure during the actual examination.