This paper formulates and tests a model of the factors influencing organisational capacity to use an ERP system effectively in the years after go-live. Three large organisations’ post-implementation studies into end-user training were used as preliminary validation of this model; and to highlight the proposition that users’ ERP knowledge and skills will degrade in the absence of a systematic approach to ongoing training and support. The analysis also found that the negative effects of staff attrition and turnover offset the positive initiatives to enhance end-user competence in the most proactive organisation studied.