You can find out what your traffic is costing you without changing anything you serve
A shadow run scores your real requests against the engine while they carry on being served exactly the way they are today.
The reason most infrastructure decisions take a quarter is that finding out is itself a risk. Someone has to put something in the path of real traffic, and the moment that happens the question stops being technical and starts being political.
A shadow run removes that. Your requests are scored against the engine and still served the way they always were. Nothing you depend on moves. At the end you have a number for what would have happened, on your own traffic rather than on a benchmark population, and you have not spent a single change window to get it.
The result is yours in a way a published figure never can be. Our numbers describe our engine answering our benchmarks; a shadow run describes your system. Both are real, and only one of them is an argument about your bill.
If it turns out there is nothing to save, that is a finding too, and it costs you a configuration change to discover.