A regular at my shop in Portland told me my sourdough starter smelled 'off' and saved my whole batch from going bad.
She pointed out a faint acetone note I'd missed, which meant the starter was starving, so I fed it right then and the loaves turned out perfect. Has anyone else had a customer catch a mistake you were about to bake with?
That acetone smell is so easy to miss when you're used to your own starter. Good on that regular for speaking up. It's a huge save, both for your product and your time. Customers who care that much are the absolute best. Makes you feel like a real community, not just a transaction.