Ask most people how they developed expertise in their field, and the answer is often a combination of practice and informal learning. Informal learning has been described in many ways. Broadly, it is implicit, opportunistic and unstructured learning that takes place in the absence of an instructor or classroom. It also has been defined more narrowly as learning which takes place in the work context, relates to an individual’s performance of their job and/or their employability, and which is not formally organized into a program or curriculum. Perhaps it is best defined by Eraut’s typology of non-formal learning (Table 1).