Cost overruns rarely come from one big mistake. They come from dozens of small, untracked decisions on site. The fix is not a bigger spreadsheet — it is shorter feedback loops.
1. Budget by category, not just by project
A single project number hides where money is going. Split budgets into materials, labour, equipment and overheads so variances point to a cause.
2. Record expenses the day they happen
Receipts that wait in a pocket for a week are receipts that get lost. Capture them on mobile with a photo, the same day.
3. Separate committed from actual
Approved purchase orders are money already spent in practice. Track committed amounts alongside actual spend to see the real remaining budget.
4. Put approval limits on people, not roles
A senior PM and a new PM should not have the same approval limit. Per-person limits keep big decisions with the right people.
5. Review variance weekly
A weekly ten-minute look at budget vs actual by category catches problems while they are still cheap to fix.