YES, I definitely recommend using a scale. In fact, I don’t recommend trying macarons without one. There are already quite a few variables in the macaron making process, and using a scale ensures that incorrectly measured ingredients are not going to cause issues. Weighing by cups or volume can vary on how much of an ingredient is actually being measured. For example, if your powdered sugar is super dense and clumped together, you could have significantly more in 1 cup worth than if you were to measure out the true weight on a scale. Egg whites can also vary in weight, and using a scale removes the guesswork.