roaches.....can't seem to get rid of them .....?

I live in a 200 apt. high rise bldg. and it seems the roaches are taking over. No matter how clean you are in your house they continue to invade. The professional people have sprayed, I spray, they keep on coming. I know from experience that they do travel from apt. to apt. but gee whiz, how do you keep those little boogers from invading your apt.