When we got our house, I noticed that a lot of the baseboards that needed to be caulked. The worst was right behind our bed which I'm sure is where most of our spiders came from. I didn't want to use silicone because it's not water-cleanup (and typically not paintable either), so I chose siliconized latex caulk instead. There also was a spot that was more like a hole between where the baseboards end and the French door begins. I saw a roach escape into it and it probably uses that entrance like a dog uses a doggy-door. But now it's sealed for good.