In law firms, the number of hours that associates work reportedly plays a preponderant role in promotion decisions. We build on previous research in this area by distinguishing the effect of ‘development hours’ from ‘billable hours’ on promotions and by assessing the extent to which billable hours are still important criteria today, in digitalized environments where efficiency is, presumably, likely to matter more than working long hours. We also examine whether certain types of behaviours, like associates' interactions with technology, may be associated directly or indirectly with a higher likelihood of promotion. We studied these questions in the context of a large corporate law firm in continental Europe, focusing on the promotion of 93 lawyers between 2005 and 2010. We found that both billable and development hours are still significant positive predictors of promotions and that associates' ability to use the case firm's computer‐mediated knowledge management system productively is indirectly rewarded by promotion. This research reasserts the fundamental role of billable hours as one of the primary means for evaluating lawyers' work and suggests that using knowledge management systems gives associates an edge in the race for promotion, particularly in law firms moving along the ‘evolutionary path’ of legal service, from bespoke to commoditized work (Susskind, R. (2010). The End of Lawyers? Rethinking the Nature of Legal Services. Oxford: Oxford University Press).