I don't think you can keep them out without hermetically sealing up your house and that is a bad move as pollutants from internal activities build up. Open a window or door and in they come.
There's always going to be small cracks and cranies where they can get in, gaps between floorboards or where the skirting boards meet the floors.
As has been said they do a job of keeping the insect population in check. Except for the bigger ones that I take out with my bug-a-salt gun.
__________________
History is much like an endless waltz: The three beats of war, peace and revolution continue on forever.
However history will change with my coronation - Mariemaia Khushrenada
