Management of enterprise resource planning (ERP) projects is exceedingly challenging due to their large scope and complexity. Schedule and cost overruns have been widely reported in ERP implementation for years. Not only are resources critical to successful ERP implementation, but the post-implementation requires substantial resources as well. However, the resources required to maintain and extend ERP systems after implementation are not well understood, especially in the presence of software customizations which increase the total cost of ownership. This research applies system dynamics simulation modeling, focusing on the rework cycle, to data of a case study toward three primary goals. First, it contributes to both the system dynamics literature and the pre-packaged software literature by exploring the post-adoption ERP environment and extending the task rework cycle. Secondly, it develops a simulation model, grounded in ERP literature and in well-established system dynamics project models, helping practitioners and organizations in making more informed customization decisions by giving them a tool to better assess the long-term resource implications of ERP customization. Lastly, it addresses research gaps recently identified regarding issues such as customization, project evaluation, effort estimation, impact of adoption, system maintenance, performing updates with enterprise apps, and potential reasons for system abandonment.Organizations typically purchase enterprise resource planning (ERP) software in an effort to improve operational efficiency and effectiveness (Sammon & Adam, 2005). Management of ERP projects is exceedingly challenging as these systems are known for being large in scope and com-