A hungry horse makes a clean manger.

Strong need makes a person thorough in using what is available. Like a hungry horse that leaves no feed behind, someone under real pressure is unlikely to waste provisions, opportunities, or help.

The saying can commend economy born of necessity, while suggesting that abundance may encourage pickiness or neglect. It is usually figurative, but its image of hunger and scarcity calls for care: applied to another person's hardship, it can sound insensitive or judgmental.

Use it when scarcity or urgency leads someone to make full use of food, supplies, or an opportunity. It may be approving, but avoid directing it at a person whose need or lack is being discussed, as it can sound pointed or insensitive.