Small roaches are a nuisense, but large ones are just gross. Sadly, they are hard to prevent, because they dont grow to the size on your' property. They grow down in storm drains and come out when things get a bit dry down there. When that happens they storm your yard, and house where there is much more moisture.
So where do those larger cockroaches come from? The ones that you see scurrying across the pavement at night, or in your garage, or in your house? Every house in your city is connected by a storm drain; these storm drains obviously collect water during rainy season but they store it throughout the year. This allows the roach population to breed exponentially year-round, and eventually, when it dries out in the summertime, possibly when a drought comes along, they'll scurry out of the storm drain move into your' yard where there's more water, and eventually migrate into the house putting pressure inside on the home.