Have you ever wondered how pest control service would kill those creepy-crawlies? Most of the people have encountered various kinds of pests in their lives. Most of the people would not consider it a pest, unless it actually causes damage to their property. As a result, having a couple roaming around has still been deemed normal instead of harmful, but certainly not hygienic.
However, at some point these pests would begin to multiply themselves in no time or start calling out the entire clan to spend some time in your house/property. They would try to oust you from your own property. They might do it as well, if you fail to manage the problem.