Before anything gets built, we write down what the problem is costing today, pulled from your own records, and we agree on that number together. It sounds like a small step. It's the one that makes everything after it provable.
Most engagements skip it, on purpose or by accident, because it's easier to talk about the fix than to sit with the current number long enough to pin it down precisely. But without that starting figure, nobody can ever say for certain what an engagement actually recovered. The after only means something if the before was real.
So the first stretch of any engagement is slower than it looks like it needs to be. That's deliberate. A number that took real time to verify is a number worth reporting against every month after.