Once pests are sighted, it may be an indication that the population has grown out of control. When one pest is seen, it is usually a clue that the infestation is large enough for pests to seek new nesting sites or food sources. The initial service is designed to flush out pests currently present in and around your home. The products used has the benefit of a long residual, meaning that the products will remain on the surfaces (invisible and odorless) where pests will continue to come in contact with them long after application. The number of pests will greatly drop after the initial service and dead pests will be seen shortly after application demonstrating the effectiveness of the products, however; this process will continue for several weeks after the initial service as the pests continue to be flushed out. Of course, after the original infestation has been eliminated, pests will continue to enter your home in search for sources of food and water and an occasional sighting may occur. This emphasizes the importance of the regular follow-up services to maintain the exterior barrier and prevent entrance to your home.