The factors that affect demand include changes in income, taxes, advertising, the price of substitutes, the price of complements, and tastes and preferences. These factors can influence the quantity of a good or service that consumers are willing and able to buy. For example, an increase in income may lead to an increase in demand for luxury goods, while an increase in taxes may decrease disposable income and reduce demand. Changes in advertising can also impact consumer preferences and influence demand. Additionally, the price of substitutes and complements can affect the relative attractiveness of different products, thereby impacting demand. Overall, there are numerous factors that can affect demand, including external factors like weather conditions.