Evergreen content
Evergreen content stays valid over time without depending on news or dates. Produced once, it sells for years with minimal upkeep.
It contrasts with cohort or news-driven content, which expires. A fundamentals course is usually evergreen; one covering the features of a tool that changes quarterly is not.
The upside is scale: it can sell on autopilot. The downside is that it ages quietly, so it is worth reviewing on a fixed cadence rather than waiting for complaints.