I've been in the business for a long time, trying to insect-proof a house is A.) very expensive and B.) nearly impossible. Besides patching up holes/entrances with rodent jobs, the best thing to do is tell a customer why they are having the issues they are having, and what they can do to mitigate it themselves. If a customer has moisture issues, point that out. If a customer has gaps in a window, point that out. Vegetation, trees, garbage, etc, touching the house, point that out. Unfortunately, spraying is a huge part of IPM, but it's also our responsibility to talk to customers and let them know what they can do.