At least you dont have to worry about 4 inch long roaches like this.
But on a serious note the pest roaches multiply very quickly and very fast. They like to emerge at night to eat the crumbs, and the rule is you see 1, there are 100 more hiding.
They like to hide in between stoves,microwaves, and toasters, all for heat.
One pregnant female roach is all it takes to get an infestation going, she can be pregnant for life! You also find roaches in beer stores too.
I knew someone who had roaches and without fumigation they never got rid of the roaches. Thats how hard they are to kill. In large infestations it takes two doses of fumigation and this bait they eat that quickly spreads a disease and kills more of the other roaches.
Roaches like to hide in colonies, they all sleep together. The ones you find running around during the day are looking for more space or there is a food shortage. In general seeing them during the day means you have a REALLY bad infestation!
Most likely you have either the american or german roach, but here are more possibilities.