If a person doesn't already have a dog, telling someone to get a dog for security is misdirected advice. Dogs are like kids. You don't just get a dog for the sole purpose of security. It won't work like that. Over 99% of the time with a dog will be spent loving the dog in a way that has zero to do with security. If you're not a dog person and you can't provide that love that has nothing to do with security 99% of the time, then I advise DO NOT get a dog.