Count not your chickens before they are hatched.

The image warns that eggs may not produce all the chicks someone expects, so counting them in advance can give a false sense of what one has.

More broadly, the proverb cautions against treating a possible success or benefit as certain before the outcome is known.

Use it when someone is making plans based on a result that has not yet happened. It encourages them to wait for confirmation before committing to those plans.