Metrics
Vacuum Effort
Before you can see how expensive a change is today, you need a baseline: how much would this change cost if the product were perfectly modular, with no hidden dependencies and no coordination overhead. That baseline is Vacuum Effort. It is the time the change should take, measured in hours.
Imagine adding a new field to a customer profile. In a clean system the change touches one file, one test, one deployment. That time is Vacuum Effort. Multiply the hours by the loaded hourly rate and you get the dollar version: what these finished changes should cost with the right architecture.