Demand is a powerful force in a free market. In three to four sentences, explain some of the factors that cause changes in demand and why it is important for consumers to understand these changes.

Changes in factors like average income and preferences can cause an entire demand curve to shift right or left. This causes a higher or lower quantity to be demanded at a given price. Demand curves relate the prices and quantities demanded assuming no other factors change. It is important for consumers to know this information, because it is crucial for them to know what they can afford and can't afford.