Whether you've opted for a small tabletop or a large 7ft tree, knowing how many lights you need for the density of your tree can make all the difference to the display. For example, Diaz from Balsam Hill states, "generally speaking, an average 7ft tree of medium density will need around 900 lights. For a brighter look, you might want to add more or less for lighter coverage."
But it's also important to always check the length of the lights to ensure you have enough to get from the top to the bottom. Emily recommends, "using 20 meters of lights to illuminate a 7ft Christmas tree".