We never had to spank our kids, in terms of more than two whacks. Generally the threat (followed by the reality) of one or two good whacks on the butt became sufficient.
We were fortunate in that we have a family where I (the dad) AM the authority in the home as far as the kids know ... and so do their friends. They all know I have rules, there are consequences of breaking them, and I never ‘threaten’ ... only promise. If this, then that. Questions?
It has worked well through the years.
Some kids, for whatever reason, NEED/REQUIRE more direct and severe consequences in order to shape their thinking and bend their will.
My wife grew up in fear of being asked to “go cut me your switch”. They would try to run from mom or dad while being switched ... even though mom or dad had them by the arm. I never saw it, but it sounds kinda funny and my wife certainly has no ill effects from it.
I believe it's a reflection of the household they grow up in.
I've never had to use physical force to discipline either of my kids and we constantly get compliments from others when we're out on how well behaved they are.
We don't scream, we don't hit each other, and we recognize the need to treat each other with dignity and honesty.
Some of their friends, though, the home is a hurricane of chaos, and those kids probably do need corporal punishment.