Many previous studies have pointed to unsustainable information systems in developing countries, meaning that software is not used after some time. When a system fails in one of seven identified dimensions, people will not use it, hence these are unsustainability criteria. This paper reports from three health information systems having been adapted to a changing environment over more than a decade. Data is collected from documents and from three of the authors' experience and systematized and analyzed by the other authors. Sustainability was redefined to mean the ability of an information system to adapt to new requirements, where software replacement may be one of the adaptations made. Factors which contributed to sustainability were found in the seven dimensions for unsustainable systems. Taking advantage of findings from other literature, including more stakeholders in the system was identified as an additional strategy for sustaining the systems.