A warranty register that writes itself

If you sell anything with a warranty on it, you have a warranty register somewhere. Usually it is a sheet with a customer name, a serial number and two dates, kept by whoever remembers, and wrong by the second month, because keeping it means somebody typing out, after every sale, facts the invoice already knows.

When a customer rings up eighteen months later and says the machine has stopped, the question is simple and the answer is a search through old invoices.

A warranty has a standing (what you decided about it): active, claimed against, or voided. And it has cover today: whether it is live this morning, which the end date decides and nobody sets.

Keeping those apart matters more than it sounds. Expired is not something you choose; it is something the calendar does. So it is not in the dropdown, and it is worked out fresh every time a screen is drawn, which means the register cannot show a green “Active” beside a row saying cover ended eighty-four days ago, and there is no nightly job to go wrong.

The end date is not typed either. It is the start plus the term, recalculated whenever either changes. A warranty that expires the day before it began is not a thing anybody should be able to save.

No. Items without a warranty period behave exactly as they did and raise nothing. No existing invoice, item or customer was changed, and no warranty is created for anything sold before the item carried a period. The register starts from the day you fill one in.

Warranty is its own module and needs Inventory, because a warranty is a promise about goods. Switch it off and nothing else notices.