Every guide says model scenarios and hold a reserve. None explain why businesses set one number anyway. In Australia the reason is structural: the financial year ends in June, so the peak quarter is funded by a figure approved five months early. Plus the marginal ROAS problem that makes a single budget fail.

Every Q4 checklist tells you what to fix. Almost none tell you what to stop touching, or when the window closes. Every change resets learning, which costs a week in September and the quarter in November. What to fix now, what to freeze from mid-October, why September decides Q4, and the Australian dates most guides miss.