A postdoc’s funding typically lasts 2-4 years: just enough time to start and finish a project and push it through to get published. In an ideal world, the postdoc who wants to become independent would then write a grant on what they have become an expert on. This, presumably, would be based on their most recent publication. However, it is rare that supervisors let postdocs take their projects with them, an issue which is most often not openly discussed before the start of the project. Here, a comment by Professor Ben A. Barres on what PIs, funding agencies, and young scientists should do to support a culture of good mentorship that enables young scientists to choose the right lab and to flourish in their chosen field.