Political interest often crystallizes during the formative years of adolescence and early adulthood, known as ‘impressionable years’. The transition into the labour market may slow down the development of political interest due to heightened cognitive demands and reduced availability of mental resources for reflective and intellectually demanding activities, such as political engagement. This paper investigates how entering the labour market affects the trajectory of political interest among young individuals in the United Kingdom. Using panel data from the British Household Panel Survey (BHPS) and employing matching techniques and difference-in-differences analysis, the study isolates the impact of labour market entry from socioeconomic background effects. Results suggest that the mental exhaustion associated with work, compared to activities such as studying, slows the development of political interest, highlighting the cognitive trade-offs of workforce participation. These findings contribute to the literature on political socialization and underscore the implications of labour policies for fostering democratic engagement.