don't count your chickens before they are hatched

The phrase "don't count your chickens before they are hatched" is a proverbial expression that advises against making plans or assuming a favorable outcome before it has actually occurred or been achieved. It serves as a reminder not to be overly confident or presumptuous about something that is uncertain or not yet realized. The metaphor of counting chickens before they are hatched refers to counting the number of expected chicks in a clutch of eggs before they have hatched and fully developed into chickens.