I don't know if that's what they mean, but the pest control guy advised me to put poison in every single room, and in large rooms at several locations as often

I don't know if that's what they mean, but the pest control guy advised me to put poison in every single room, and in large rooms at several locations as often you will not know where they really stay/forage. E.g. you might notice the one mouse that goesi in the kitchen but not the others that live in the attic. Then again, maybe he was just trying to sell more.