Dairy products (milk, cream, yogurt, cheese) have different fat and water percentages. Volume hides these differences; weight keeps sauces, batters, and doughs consistent.
Fat content shifts density; pick the correct milk/cream/fat level if variants exist.
For cheese, shredded vs grated vs cubed changes volume—prefer grams.
Does fat percentage matter?Yes. A cup of heavy cream is heavier than milk; swapping without weight alters richness and texture.