German and American cockroaches orient to millimetre-scale edges—drains, kickboards, gasket folds—not only “dirty kitchens” broadly.

Common risk points to audit weekly

• Sink drains and overflows holding biofilm and moisture.
• Trash bins with overnight organics or loose liners.
• Pipe and wire penetrations behind cabinets linking to common risers.
• Gaps under appliances where heat and crumbs combine.
• Cabinet hinges and blind corners for daylight harbourage.
• Crumbs and spills along kickboards and tile grout.

Reduction rhythm

Pair detergent breaks on trail zones with technician gel maps; vacate harbourage clutter before technician visits so baits remain inspectable.

Closing line from visual: removing resources and sealing highways keeps cockroach pressure low between professional cycles.