Large-scale research infrastructures (LSRIs) form a vital backbone of scientific research and increasingly rely on robust digital infrastructure for their operation and exploitation by the research community over multiple years. However, building and maintaining LSRIs poses a multi-disciplinary challenge: You understand how you want to advance research in a specific domain, and you have found your partners. But how to find the expertise to build and maintain the technical infrastructure? How to govern and sustain it? What are the available infrastructure and tools that can be reused?