German cockroaches live in the warm spots you cannot see: behind the dishwasher motor, inside the fridge cavity, under the bench overhang, in the gap beside the oven. A floor spray does almost nothing to them. Gel bait into those points works, because whatever feeds carries it back to the rest.
Australian and smoky brown cockroaches come in from outside through drains, weep holes and around the switchboard, so that is a perimeter job instead. The cafes and food premises along the Ocean Grove and Barwon Heads strips run hard through summer with bins filling faster than they do off-season, and that is when the calls come. Kitchen prep decides the result as much as the treatment does.
