The answer to 'why do I have extermination' is that you likely have a pest infestation in your home. Common causes of pest problems include food sources, moisture, and entry points that allow pests to get inside. Symptoms may include seeing pests, finding droppings or nests, and damage to your home. Solutions can include sealing entry points, removing food sources, and using traps or pesticides to eliminate the pests.
For minor infestations, some DIY pest control methods may work. However, for larger or more complex pest problems, it's best to call in a professional exterminator. They have the expertise and equipment to properly identify and eliminate the pests in a safe and effective manner.