The well-known proverb “measuring is knowing” holds true in many instances, as it elevates the discussion from a subjective assessment of a particular problem to a more quantitative approach. In practice, this approach has proven to be effective. For example, we use the degree of luminal coronary artery stenosis to guide the need for conventional angiography and potential revascularization. Similarly, we use standardized thresholds for aortic dimensions to determine the need and frequency of follow-up, as well as to help us identify the best possible moment to proceed with an intervention. In these examples, measurements are an essential component of established guidelines, allowing us to make informed decisions and optimize treatment plans.