The intensity of health care utilization is often reported as rates of use or dollars spent, but those measures have less intuitive meaning for an individual older adult. The measures presented in this section are intended to demonstrate how older adults actually experience care. The number of contact days is a patient-centered measure of the frequency of interactions with the health care system. Contact days are defined as the number of days a patient spends per year in an inpatient setting or having a clinician visit, procedure, imaging study, or lab test in an ambulatory setting. By measuring how many different days in a year older adults seek or receive some type of medical contact, we can begin to appreciate how much of the older adult’s daily life is being occupied by health care.