Debriefing is an important part of reviewing and improving performance. There should be a debrief whenever there is a chance to improve standards of service delivery. See National Operational Guidance: Fires and Firefighting.
Commanders should choose an appropriate format for the review. They should conduct it in a way which encourages open, supportive and constructive discussion. If the review covers individual performance, discuss it against the standards for that role and acknowledge good performance and conduct worthy of merit.