Radio 4’s Analysis programme this evening asked what happens when companies lose the knowledge, skills and understanding of experienced staff. The programme evidenced that the know-how existing outside of manuals and policies was important to institutional sustainability. Similar issues of lost expertise are relevant to schools. The most successful staff room (and profession) is one that balances experience, expertise and new thinking in a creative tension. New teachers are very important and offer a great deal to schools but we also need staff who have the experience to guide and inform others so that the school does not lose sight of the fundamental importance of child development, subject and relationship. Without experienced staff, schools can throw away success and repeat mistakes of the past. We need staff with expertise developed over time that is valued and creates aspiration for others. We need staff whose expertise is valued in the classroom and in leadership. We need slow-tracked professionals.