This study is the first of its kind to analyze and compare demand-driven acquisition (DDA) ebook programs on a large scale by using eight academic libraries. The purpose is to understand which factors contribute to successful collection management practices and sustainability. Study findings also offer insight into weeding practices and suggest that ebooks removed from the discovery pool too soon may impact service to library users. Furthermore, findings based on formula analysis show that return on investment (ROI) for serviceable content is better achieved through a sustained straight DDA model without short-term loans.