For most contractors and trades businesses, the real profitability of a job doesn't become clear until after it's finished — final costs are tallied, compared against what was billed, and the margin is whatever it turns out to be. By that point, there's nothing left to do about it except try to remember the lesson for the next bid.
Why change orders are where the margin actually leaks
The most common way a profitable-looking job quietly turns thin is unbilled or under-documented change orders — a client asks for something extra, it gets done because saying no mid-job is awkward, and it either never gets invoiced or gets invoiced for less than the actual cost of the additional work. A single "verbal only" change order on a tight-margin job can be the difference between a solid profit and a loss.
What tracking a job in real time actually catches
A job costing system that flags margin risk while the job is still running — not just at closeout — turns a lagging indicator into a leading one. A job trending toward thin or negative margin at the halfway point is still something that can be managed: a scope conversation with the client, tighter labor allocation on what's left, or simply going into the next bid with better information.
Why ranking jobs worst-to-best matters more than looking at them individually
Reviewing jobs one at a time makes it easy to miss a pattern — the same type of job, or the same crew, or the same client consistently running thin. Ranking every active and recent job by margin surfaces that pattern immediately, in a way that reviewing job folders one by one usually doesn't.