According to Pittsburgh city of public works, prevention is better than cure when it comes to rodent control.
Rats and mice have the ability to get through very tiny openings. They have the capability to squeeze through openings as small as half an inch or one inch in diameter for a mouse and rat respectfully. Therefore, it becomes very important to plug these gaps both inside and outside of the house.
If you already have an infestation then this becomes an essential part of getting rid of any rodents. Keep checking the holes that you have plugged to make sure they haven’t been opened up again because rats can chew their way through anything and have a look here to read more about pest control for the home.