GGB The full journey takes as long as fit-out and licensing dictate, but the controlled countdown — the phase run against a readiness board — is the final six weeks or so. That is the window in which people, product, compliance and systems either converge to an evidenced standard or quietly slip. In our experience, compressing that countdown is where openings wobble: training and soft launch are the items that get squeezed, and they are the two that guests actually meet.
From The 45-Day Pre-Opening Discipline: What the Last Six Weeks Decide — the full reading, with the method behind this answer.