The paper deals with the changes in class quality during a working day or a week. In the first part of the paper notions of quality and changes are analyzed. In the second part, teachers' personality traits are investigated along with the class quality. Data obtained during the investigation of teachers working in primary and secondary school was analyzed and the results are presented in the tables along with the statistics. The results show that teachers relate the class quality to pupils, timetable, teaching units and teaching equipment instead of the educator and teaching methodology. Therefore, the conclusion points out the need for teachers' further professional advancement.U radu se razmatra pitanje promene kvaliteta časa u toku radnog dana ili nedelje. U prvom delu se analiziraju pojmovi kvaliteta i promene. U drugom delu rada karakteristike ličnosti nastavnika se dovode u vezu sa kvalitetom nastavnog časa. Dat je tabelarni prikaz i analiza podataka dobijenih ispitivanjem učitelja i nastavnika u osnovnim i srednjim stručnim školama i gimnazijama. Podaci ukazuju na to da nastavnici kvalitet nastavnog časa prvenstveno dovode u vezu sa učenicima, rasporedom časova, nastavnim jedinicama i sredstvima umesto sa nastavnicima i izborom metoda njihovog rada. Stoga se, u zaključku ističe potreba daljeg stručnog usavršavanja nastavnika
