A 7ft tree is a great size for a Christmas tree! The number of lights you need will depend on the type of lights you're using and how many strands you want to use. Here are some guidelines: For mini lights, you'll need approximately 100-200 lights per foot. For rope lights, you'll need approximately 2-3 feet of lights per foot of tree. And for LED lights, you'll need approximately 50-100 lights per foot. Ultimately, it's up to you to decide how many lights you want on your tree!