0.07 inches of spine misalignment cost an entire print run

The failure, with a number attached

One documented failure: a printer's wrap, designed for one printer, was reused on another printer's stock, and 0.07 inches of spine misalignment cost an entire print run. The text was visibly off-centre on every copy. That's the kind of fiddly, easy-to-forget detail that gets skipped because it looks too small to matter, right up until a warehouse full of stock proves otherwise.

The fix: recalculate the spine for the exact printer and paper stock in use, every time either one changes, and order a physical proof before committing to the full run. Trusting a spine measurement that worked on a previous printer is the exact assumption this failure disproved.

Contents pages carry the same discipline, earlier in the build

A contents page is generated after layout, never typed by hand before it. You can't know what page a chapter starts on until the whole thing has genuinely been laid out; typing a guess in early just means fixing it later, by hand, on every edition at once. Both failures share the same root cause: a physical production detail treated as fixed when it actually depends on something that changes between runs, printer, paper stock, or the layout itself.

What done looks like

Spine width is recalculated against the exact printer and paper stock for the current run, with a physical proof ordered before committing. The contents page and folios are generated from the finished, laid-out document as the final build step, never typed in before layout is complete.