This is an edited version of the 25th Goff Lecture delivered on 27 October 2020.1 It discusses the late Professor David D Caron’s ‘Rule of X’, an ethics-based benchmark aimed at discouraging acceptance of an excessive number of arbitral appointments and promoting their more equitable and diverse distribution, along with professionalism. The article reflects two ‘firsts’ in the history of the Lecture series: to have been delivered both online and by a woman - the latter prompting Neil Kaplan QC to comment that the prior absence of female Goff lecturers had been an “egregious error”.