How do prompt variables make AI prompts reusable?

Prompt variables are clearly named placeholders such as {{product}}, {{audience}} or {{visual_style}}. Replace every placeholder with specific, accurate information before submitting the prompt to an AI model. Good example values show the expected level of detail, while a completed sample demonstrates how the prompt should read without placeholders. Variables improve consistency, reduce rewriting and make a prompt easier to adapt across clients, campaigns and creative formats.