Whilst much research on teachers' lives has focussed on their early years in the profession, much less attention has been paid to those in their later years, so called "veteran" teachers. Yet, many of these are likely to hold positions of responsibility in the school, receive greater remuneration and have experienced the impact of more policy and social change in their work than many of their less experienced colleagues. More importantly, their resilience and effectiveness are likely to have been subject to more sustained challenges. Drawing upon a range of research, this paper seeks to investigate how and why teachers in the third and fourth decades of their professional lives sustain or do not sustain their beliefs and sense of commitment to teaching at its best. (Contains 2 figures, 1 table, and 4 notes.)