This paper deals with the time students spend working at home for school. In Study 1, we investigated amount and regulation of time. Study 2 serves to validate the results of Study 1 and, in addition, investigates the duration of the time units students used and their relation to scholastic success. In Study 1, the participants were 332 students in Grades 5 to 11; in Study 2, we investigated 280 students, Grades 6 through 10. To measure the time students invested we used diary entries. Results proved that students use the majority of their time to prepare for exams and to complete homework assignments. In Study 2, three working types could be identified, which are also characterized by differences in scholastic parameters. Those students who predominantly work in 0.5-hr units show the best scholastic performances. (Contains 3 tables and 3 figures.)