Bed bugs are surely a pest that can be difficult to get rid of, but they can be increasingly difficult if you frequently visit a home with bed bugs and carry them back, or if you share a complex with neighbors.
There are multiple reasons that play into this question. For example, if you frequently visit a home that has bed bugs that you're not aware of, then you can reintroduce them to your home every time that you come back, even if you're paying to have them taken care of. Other reasons are if you live in an apartment complex, multi-housing, and you share walls with your neighbors. If they have bed bugs and they're not treating them properly, they can continue to be pushed back into your home on a reoccurring basis.