This chapter presents an analysis of how both information-processing and generic skills are used in the workplace. In fact, the distributions of skills use for workers at different levels of proficiency overlap substantially. As a result, it is not uncommon that more proficient workers use their skills at work less intensively than less proficient workers do. Over-skilled workers - those with higher skills than required by their jobs - tend to under-use their skills, resulting in a "waste" of human capital, while under-skilled workers - those with lower skills than required by their jobs - have to work harder to accomplish their tasks, which could lead to stress and lower job satisfaction, with negative consequences for productivity.