I have moved.  I again am living alone (me and the left over roaches.)  My apartment is most likely slightly toxic at the point.  I have boric acid along all the walls, I have cans of Raid in the kitchen and the bathroom.  I have bug bombs, roach bate and of course the ever present "squishing shoe."  I have noticed a significant decrease in la cockaracha activities.
The previous renter was a smoker.  I know this not only from the strong smoke odor emanating from the very walls but from the tar deposits I've scraped off the windows.  I decided the best thing for me to do to mask this ever present odoriferous experience one senses upon entering my domicile was to plug in a scented oil warmer conveniently equipped with a tiny "super quiet" fan.  It emits the scent of a "Tropical Breeze." 
Now when one enters my apartment he has the sensation of a heavy smoker with a can of Raid and a death wish to any bug that crosses her path standing just up wind of a refreshing tropical breeze.  Pleasant, Yes?