I always take a gander at who's standing on my porch and can do so without being seen. If it's someone I don't know I generally let the dogs answer the door. With all their sniffing and barking and the beware of dog sign salesmen and other 'undesirables'
tend to find another house to approach. Friends on the other hand know they are a couple of ankle biters that would just as soon be petted as to chase anyone and are allowed enter without fear of bodily harm. Dogs are good to have around.