The best way to keep mice away is to seal up potential entry points of homes and structures. Entry points can easily be found by checking interior walls for light coming through small cracks and by feeling the interior air for movement. It is also a good idea to contact a professional exterminator for a full assessment of potential entry points for mice and other rodents.
Small cracks and holes can easily be sealed up with inexpensive caulking material. In addition to sealing up entry points, it is always a good idea to cover up all windows with screens, as well as cover drains with 1/4 inch of meshing material, as mice are too large to slip in through the mesh. Mice enter homes and structures in search of food, water and shelter.
Mice are also known to take up residence in outdoor garbage cans, sheds, wood piles and junk cars. It is always important to keep outdoor trash cans and wood piles tightly covered and sealed. Many people make the common mistake of leaving pet food in dishes outside. Pet food not only attracts mice, but it also attracts raccoons and possums. This can be easily avoided by clearing pet food dishes as soon as the animals are finished eating.