Using a unique dataset collected from a large classified ads website in China, we investigate the future purchase probability of coupon redeemers, particularly how it differs between users who redeem coupons right after the coupon drop and those who delay redemptions. We find that, coupon redeemers have a higher probability to make future purchases than non-redeemers no matter on which day the coupon is redeemed. But users with the largest future purchase probability are never those who redeem coupons at the date of release. In other word, users with high demand of products tend to postpone redemptions. And this tendency is found to be much higher in holiday seasons. Regret theory is used to explain this phenomenon. Finally, we make a preliminary test to verify the existence of users who are likely to delay redemptions.