This paper aims to (1) compare implementation considerations and challenges for metal and polymer rapid manufacturing (i.e. the use of additive manufacturing technologies for final part production) for mass customisation and (2) derive decision trees for firms seeking to implement such an approach. Implementation data from 10 case studies from the dental and hearing aid industries has been captured and used as the basis for the comparison and design of the decision trees. Our objective is to provide evidence on the use of additive manufacturing technologies as enablers for mass customisation and to provide practitioners in industry with guidelines for decision-making on how to install and ramp-up mass customisation production with these technologies. Common considerations and challenges for both metal and polymer applications have been identified. Based on these insights, eight implementation decision trees have been created and represent the main contribution of this paper.