All predators live where there is prey. If there are spiders, look for what
they're eating, get rid of that, you get rid of the spiders. (Same with
roaches, mice, etc.)
 
When we moved to the SE coast 20 years ago, we rented a seriously drafty
house that was about as good as living outside for the bugs. When we turned
the lights out, the mosquitoes would buzz after us like crazy for about 15
minutes while we kept the cover over our heads. Then the buzzing would stop
and we could uncover ourselves. That was because the spiders had come out of
the walls and feasted on the skeeters by that time.
 
The landlord installed new windows and a new A/C system, I sealed every
crack in the interior walls, and all the spiders were gone in no time.
 
Daddybob