For a quarterly spider service program, I recommend using an appropriately labeled, microencapsulated liquid insecticide at least twice a year. Removing webs prior to treatment will help facilitate control.
Most arthropods, including spiders, do not want to be inside the structure. Thus, exclusion practices are the first step to prevent intrusion. For product application, however, focus around the outside of doors and windows when treating with your perimeter spray. Aerosols, especially those with microencapsulated formulations, are a good choice for hard-to-reach crevices.