A first order proves you can supply. A second order proves it sells. Those are different facts and only the second one is worth building capacity around. Plenty of producers have taken one order from four shops and concluded they have a wholesale business, then spent a year waiting for reorders that were never coming.

The record you keep here is also the most persuasive document you own. A lender, a landlord or a larger buyer will take twelve rows showing an account reordering every five weeks more seriously than any projection you could write. You are not keeping it for the milestone. You are keeping it because it is evidence.

You need at least one account that has ordered more than once, or a standing order that has run a few cycles. If no reorder has happened yet, work this Guide anyway: the thing that causes reorders is knowing your sell-through, and that starts with asking.

Decide where the record lives. One spreadsheet, one row per order, for every account. Not in your invoicing software only, because what you need to see is the gap between orders, and invoicing software does not show you that.