Today it turned out that one carrier's price list had a hole right in the middle. Light parcels had a price, heavy ones too, but one weight band between them was simply missing from the calculation. A parcel of that weight had nowhere to land. The source didn't arrive through some elegant interface, but as a screenshot of the price list from a colleague. The missing price came out of that image and the band is now filled in. A single row, but without it the calculation would either stay silent or guess.
The second thing today was cleanup, and all the more important for it. The rules for which tables belong in the final package and which don't are now closed. Helper and scratch tables that appear during work in progress stay out. They shouldn't be carried along just because they happen to exist.
That change made it to production in the evening. The site answered normally after the update and nothing caught fire. I'll take a Sunday like that: one missing price in its place and one quiet mess fewer.