I don't think it is appropriate to spank a teenager. In fact, while I know many people who believe that it is sometimes necessary to spank small children, I don't know anyone who thinks it is okay to spank a teen.
you know one now that thinks it can be OK to spank a teen depending on the teen and the situation.
I never had to spank mine after they got into their teens, although I came close a couple of times. But I really think that the reason I didn't have to was the "discipline" they recieved when they were younger,
Both of them have told me seperately that they knew they were OK as long as I was yelling at them. They got worried when my voice got soft and deep.