Rodents can be difficult to keep out of structures. Mice can squeeze through spaces as small as a dime and rats can fit through holes the size of a quarter. For proper rodent pest control, seal any cracks and voids. Ensure there is proper drainage at the foundation and always install gutters or diverts which will channel water away from the building.
If you do find signs of a rodent infestation, contact a pest professional promptly. A rodent exterminator will be able to inspect your home, confirm the species and recommend a course of rodent control treatment.