Telescopes are built to do astronomy. Often this point is taken to extremes by astronomers demanding access to facilities before they are ready to receive them and often engineers dwell on aspects of a system that have little impact on the final performance of the machine. The right balance may never be found. Doing science early may scoop the competition but doing science more often may be the best long term investment. A systematic approach to commissioning has been adopted at ESO within the VLT project with the end operability and maintainability being a major driver of the activities. In this paper are presented the historical, strategic and problematic aspects of the commissioning of the VLT.