As it gets colder in the fall mice/rats have a harder time finding food such as grass and seeds. This will cause them to start looking for food in your home. Remember that a mouse can get through a hole the size of a dime and a rat can squeeze through a hole the size of a quarter. Evidence of their presence can be droppings left behind, nest made of materials such as shredded paper, "hallways" or borrows in insulation, evidence of chewing on boxes etc, areas that are stained or smell like urine in heavy infestations. According the the CDC (Center for Disease Control and Prevention) mice and other rodents can transmit a number of diseases but it can be incredibly difficult to control them on your own. Here are some tips you can do yourself. Eliminate Entry Points - Seal up any cracks, gaps or hole around doors, foundation, roof and siding. Keep Your Kitchen Clean - A clean kitchen won't repulse mice but it won't attract mice like a dirty kitchen with food bits here and there. Remember to keep dried pet food in sealed metal or glass containers so the rodents can't chew through it. Landscaping - Mice and rats can gain entrance to your home by crossing tree limbs and getting onto your roof. You should keep limbs away from you house for many reasons...this is just another one of them. You should also keep you garden and shrubs tidy and trimmed. Remove Clutter - Keep potential shelters such as rock piles, wood piles etc far from the foundation of your home to keep critters from setting up camp right outside. Remove clutter like piles of boxes etc from inside the home to remove harborage inside. If none of this helps call me and I will take care of the problem for you.