A decline in the quantity demand is directly related to a change in the price of a good or service. Specifically, when the price increases, the quantity demand decreases. However, a decline in demand can be caused by multiple variables. A few variables that may cause a demand to decline may include consumer preferences, a change in income, a change in the price of a substitute good, or a change in the price of a complementary good. An example of an item that I now buy less of is canned soda. The reason for this is that I wanted to switch to a healthier alternative, which is now sparkling water. This example shows a decline in demand as my own preferences have changed. Although the price of cases of canned soda can slightly fluctuate, any increase in price and decline in the quantity demand was never the reason for me to buy less of it