Spiders don’t just materialize out of thin air (though it feels like that at 3 AM). They come in through cracks, gaps, and holes you forgot existed.
Walk around your house like a paranoid detective. Grab that tube of caulk and seal every crack you see near windows and doors.
Don’t forget your foundation and the gaps around pipes. If you can slide a credit card through it, a spider can go to college there. Do it now.