Which of the following should be included when asking about a person's substance use?

When assessing a person's substance use, it is crucial to focus on the quantity and frequency of their consumption. Understanding how much and how often a person uses substances provides valuable insight into their patterns of use and the potential impact on their physical and mental health. This information helps in identifying levels of risk and aids in determining appropriate interventions or support needed for the individual.

In contrast, while personal preferences such as a favorite type of drink or details about their social circle may contribute to the broader picture of an individual's relationship with substances, they do not directly inform about the severity or implications of their use. Similarly, knowing the last time a person had a meal could be relevant in certain contexts, particularly regarding overall health and well-being, but it does not specifically relate to substance use patterns. Therefore, focusing on how much and how often someone uses substances is the most direct and relevant approach in assessing substance use issues.