Spank Em vs Ground Em

Punishment. What are your views. I believe it is ok to spank a child untill they are old enough to really understand that all actions have consequences. Like age 7 or so, it may depend on your kid. Then after that, they need their own physical space, and grounding should take place. Time by there self to think does wonders. By this age spanking may really damage their self image, and may even make them forget what they even got in trouble for, because they are more focused on the current pain. If you have kids or ever plan on having them. Tell me what you think.