The Rewrite

What this pack runs.

A working system that cannot be changed costs two things, and only one of them has the system's name on it. What it costs to keep running is in the IT budget. What it holds back, the products not launched because a change takes a year, the pricing changes that arrive months late, and the work done by hand around it, sits in product and operations, and no ledger records what was not done. So the rebuild's estimate is compared with the IT line, found to be five years of maintenance, and argued about. That is not the comparison. This pack turns it into two annuities and a subtraction. What the system costs to keep running plus what it holds back, across the years counted and discounted, is what carrying it is worth from here. Against it: the estimate, plus the old system carried for every year of the build, plus the new system's running cost and what remains held back after. Their difference is what the new system saves a year once it is done, across the years after the build, less the estimate, so the whole question reduces to the break-even overrun, how far over its estimate the rebuild can run before carrying is cheaper, read against the one figure the company can defend: how far over the last rebuild ran. Nine sourced decisions hold the frame: two rebuilt their own foundation and held, one rebuilt fresh and lost what worked, three carried a platform the market was leaving, one carried the platform it inherited and it was the asset, one bought the replacement, and one is the vendor ending its customers' option to carry. It stops on two halts: no one has counted what the system holds back, and no one has opened the file on the last rebuild.

The casebooks these cases come from.

The pack reads nine sourced decisions through the framework. They are drawn from these casebooks, each one a set of verified records on a single decision type.

A verified record has passed a mechanical claim-versus-source check, a second model's read, and human approval. The count is what exists today, not a target.