A lecturer's task is not confined to the classroom and he/she continues to guide his/her students after lecture hours. However, many students who are able to solve their problems independently often still seek the lecturer's guidance, resulting in negative externalities. In our paper, we examine the lecturer's attempts to minimize the negative effects of unnecessary guidances. Specifically, we deal with the optimal time allocation policy adopted by a lecturer who is maximizing his/her utility function, which is positively related to his/her students' level of utility.