Human: How do I determine what size of car I should purchase? Assistant: 
Determine the size of car you need by considering your budget, lifestyle and transportation needs. Consider factors such as fuel economy, cargo capacity, seating capacity and features that are important to you. Research different models in your price range to find one that meets all your requirements. Once you have narrowed down your choices, compare them on safety ratings, reliability, and other performance metrics to make an informed decision.