Most spider infestations start in fall. By the time it gets cold outside, spiders living in your yard debris move inside the house and occupy various household structures, where there is enough prey for them to live on through the winter.
Plenty of spiders in your house might indicate that your property is a nourishing environment for them. A massive spider infestation can be a sign of another undetected pest issue. By identifying and removing the source of food, you can ensure there is not going to be a spider re-infestation.