OpenFOAM sustainability involves developing software that meets critical needs of users, through a balance of resources, technology, investment and institutional support. The critical needs are availability, usability, robustness and extensibility. The critical work required to meet those needs are publishing, repair and redesign. Employers rarely allocate time to individuals to contribute critical work, so it is generally left to “career maintainers” at CFD Direct. With limited funding, decisions about the critical work are made by those who fund and/or contribute the work, via The OpenFOAM Hub.