This study investigates the impact of displaying grades versus not displaying grades on student performance and emotions in secondary education, while keeping feedback comments constant. Using a longitudinal design, we examined intra-individual changes in performance and emotional responses among 99 students across four classroom groups as they experienced phases of grade display and non-display. Contrary to the notion of grades solely as detrimental, our findings reveal a complex relationship. Initially, grade display decreased performance and evoked negative emotions, but these effects dissipated over time, suggesting student adaptation. Our study highlights the significant impact of feedback comments, suggesting their importance independent of grades. These results call for a sophisticated understanding of grading practices, emphasizing longitudinal research to capture the evolving effects of grades and feedback. Practical implications for educators include maintaining stable grading practices and providing preparatory guidance to mitigate initial negative impacts, contributing to optimizing educational assessment strategies.