The late return of library books is a manifestation of procrastination, resulting in fines that impact the overall user experience at the library. Overdue or lost books can disrupt the library’s circulation services and affect the satisfaction of other patrons’ book needs. This study analyzes overdue readers at Nanjing Normal University Library from 2012 to 2023, examining factors such as the frequency of overdue incidents, borrowing habits, instances of book loss, duration of overdue periods, and the gender and background of the readers. The findings from path analysis suggest that the accumulation of fines is a deterrent for overdue behavior by influencing borrowing habits and serving as a warning against procrastination. Structural equation modeling analysis reveals a positive correlation between reader self-regulation and overdue attitudes, negatively impacting book circulation. Additionally, the study observes the application of the law of large numbers to the occurrence of book overdue, with a weak correlation between overdue incidents and instances of book loss.