The problem
Your stock lives in your head.
You make candles. You bought 2kg of soy wax last month, you think you’ve used about half, and you’ve got a market on Saturday. Do you have enough wax for fifteen jars? Or twelve? You don’t actually know. You’ll find out when you’re pouring.
The spreadsheet you started — full of crossed-out numbers, half a recipe, a column you don’t understand anymore — gets opened once every three weeks. Then never updated. So you buy wicks you already had and run out of jars at the worst moment.