ESO telbib: learning from experience, preparing for the future

The ESO telescope bibliography (telbib) dates back to 1996. During the 20+ years of its existence, it has undergone many changes. Most importantly, the telbib system has been enhanced to cater to new use cases and demands from its stakeholders. Based on achievements of the past, we will show how a system like telbib can not only stay relevant through the decades, but gain importance, and provide an essential tool for the observatory's management and the wider user community alike.