Time-bound practice is crucial for effective UPSC exam preparation as it simulates the actual exam environment. By timing themselves during mock tests, candidates learn to manage their time effectively, which helps in prioritizing questions according to difficulty. This practice builds confidence and accentuates the ability to think clearly and respond quickly under pressure. Additionally, time-bound practice allows for the identification of weaknesses and strengths, enabling candidates to focus their preparation strategically for enhancing performance on the actual exam day.