The amount of Christmas lights needed to decorate a house depends on several factors. For instance, the size of the house, the number of windows and doors, and the desired aesthetic effect all play a role in determining the number of lights needed. Generally speaking, a medium-sized house with a traditional style could require anywhere from 300 to 500 lights. However, larger homes or homes with a more elaborate style may need thousands of lights to create a truly dazzling display.