To maintain employees’ health, it is important to prevent work-related exhaustion in general but also on a day-to-day basis. With a quantitative ten-day diary study, we investigated three different working time strategies as underlying mechanisms of the effects of day-specific work overload and work scheduling autonomy on end-of-work exhaustion. The sample comprised 578 daily measurements from 93 employees in Germany. Daily work overload was positively related to daily break violations, working faster and unplanned overtime. Daily work scheduling autonomy was negatively related to overtime (vs. finishing work on time/early). Work overload (and telework, which we used as control variable) and work scheduling autonomy were significantly and indirectly related to higher and lower, respectively, end-of-work exhaustion via unplanned overtime. To prevent employee exhaustion, it is important to promote good work design in everyday working life so that employees do not need to extend their working days.