I own rental property and have been left with German roach problems (and the resulting clean up) on more than one occasion. Not apartments, but detached, executive level, rental. As a landlord I've learned folks have variable (and often mysterious to me) life style habits regardless of income and education.
My best solution has been to place roach bait "hotels" under every sink base, throughout basement spaces near plumbing pipes and HVAC access and around vent stacks in the attics. Also place them in closets and discrete corners, by entrances from garage to house, behind refrigerators and stoves and under dishwashers. It seems to work quickly without spraying chemicals about. I date the "hotels" with a pen on the back. They are supposed to be changed on a schedule. If you rattle the "hotel' when it is new it won't make noise because it's full of bait. If it rattles a few weeks or months later there is still bait. If the bait is gone there is no noise again and if you have roaches they will be eating the bait. If there is a rattle, I leave the old ones and put down fresh ones. I ask the tenants to keep up with this routine. My properties are inspected at least twice a year. If the tenant does not keep up with the routine I have fresh "hotels" on hand. It's small price to pay if you've ever had to spend days with a mask, dustpan and brush cleaning up droppings and disinfecting spaces.
