Spider infestation can occur when they have access to your property, such as cracks in foundations, opened vents, unsealed entry ways and poorly fitted doors. Once in, spiders can lay eggs and increase its population exponentially. They prefer moist, dark and abandoned areas. However, some spiders prefer to set up camp outdoors where they can prey on outdoor insects that are attracted to light. So, keep a lookout, you might have some nests hiding in your bushes right now.