I agree with you all regarding infestations of vermin. They're a health risk and cause damage inside the house. But I was lucky in that the only mice and rats in my house were ones the cats had caught and brought in. Many were actually sweet little wood/field mice with very large ears. I never had any living in the house, just these one-off individuals. I even had a rat which I saw clinging to the grid at the back of the fridge. He'd climbed up there to escape the three feline monsters on the floor below. I wheeled the entire fridge towards the back door and gently waved a broom at him. He had the sense to jump down and scarper. But a neighbour had a real infestation of rats. They'd chewed through electrical wires, insulation boards, furniture, and the electrocuted ones absolutely stank as they decomposed. She had to get the vermin-control man to put down poison and within a couple of weeks they'd all gone. I'd have had to do the same in her position.