The renovation goes over budget the day you stop looking at it.
Of the three apartments we shadowed during the Moodroom beta, all three ran over their stated budget. The difference between the one that ran 8% over and the one that ran 47% over was not the contractor, the city, or even the scope — it was how often the owner had looked at the running total in the last week. The budget doesn’t blow up in a single explosive moment. It drifts, daily, while you’re choosing tiles.