Roaches are nocturnal, so if they start appearing during the day, it may indicate a growing population. Following the trail of roach droppings or observing where they are frequently sighted, especially at night, can lead you to their nesting location. Common nesting sites include behind appliances, within wall cavities, under sinks, or in cabinets and pantries. Identifying and eliminating these nests is crucial to eliminating the infestation.