Renovation budgets fail for predictable reasons: the structural work was underestimated, the contingency was spent on finishes, or nobody priced making good. None of those are bad luck.
Where the money actually goes
On a typical whole-house job, structure and services take more than half the budget and are almost invisible when finished. Accepting that early is what keeps the project honest.
Keep a real contingency
Ten percent, untouched, in writing. On older properties, fifteen. It is not padding — it is what pays for the thing nobody could see until the floor came up.
