1. Luggage and Shipped Boxes
Because of their small size, less than 1/4", they can hide in the seams of baggage when you travel and sneak a ride home with you. Boxes shipped from an infested home can easily make your home their new habitat. College dorms are a great food source for the bugs so when your college student comes home they can unknowingly have bugs hidden in bags and boxes. If you rent to a new roommate, the bugs can come along in boxes, bags and hidden in furniture.
2. Neighbors
If you visit a home that has an infestation the bugs can hitch a ride home on your clothes or in anything you bring back with you. A neighbor can bring the bugs into your home on their clothes, boxes or bags. If your unit is close to another that has an infestation the Bed Bug can crawl along pipes, on wires, through heating and cooling vents or just through the dead spaces between walls. The bugs may move between units because they have grown in numbers to a point where they need an additional food source, the resident has moved out or because the unit is sprayed to try and kill them.