What is better estimates 1 c or 1 gallon?

It depends on the context of what you're measuring. For smaller quantities, 1 cup (c) is often more practical, while 1 gallon is better for larger volumes, such as when cooking in bulk or dealing with liquids in larger containers. If you're looking for precision in smaller recipes, use cups; for larger tasks, gallons are more efficient. Ultimately, "better" depends on your specific needs.