In September 2010, five mathematics lecturers set out on a professional development project with the following aim: to reflect on teaching practice using John Mason's Discipline of Noticing. At the end of the academic year, each lecturer considered her experiences of engaging with the process. In this paper, we describe the observations made and discuss the benefits and challenges of engaging with the Discipline of Noticing, namely, the benefits of a collaborative approach; the challenges of "noticing in the moment" and the advantages of and difficulties with, writing brief-but-vivid accounts.