Interpersonal comparisons influence spending habits, causing people to try to keep up with wealthier neighbors. By analyzing household data from Germany, researchers found that when people see others spending more, they tend to spend more themselves, even if it means saving less. For every 100 euros increase in what richer households spend, people spend an extra 10 to 25 euros. This effect is strongest among upper middle class households. These findings help economists understand how our spending decisions are influenced by comparing ourselves to others.