You can often hear, see, or smell a pest problem. Scratching or rustling noises in walls can indicate a rodent infestation, as can chewed food containers and oily, dirty rubbings along baseboards. Bugs frequently manifest themselves by scurrying across the floor, flying about, or eating food, paper, or other fibers. Musty odors can also be a sign of fecal matter, droppings, or nests.
The best way to discover what exactly is causing your problems is to have a professional pest expert thoroughly inspect your home. You can then work together to eliminate the problem and prevent future infestations.