The answer to 'when to treat for rodent' is that the best time to treat for rodents is as soon as you suspect an infestation. Rodents like mice and rats can reproduce quickly, so addressing the problem early is crucial to prevent a larger infestation. Signs of a rodent problem include droppings, gnaw marks, and noises in the walls or attic.
It's generally recommended to treat for rodents in the fall and winter when they are more likely to seek shelter indoors. However, rodents can be a problem year-round, so it's important to be vigilant and take action as soon as you notice any signs of an infestation.