The time for corporal discipline is when children are quite young. A single spanking establishes that there are consequences for disobedience. That is enough for many kids. They have to know that you mean what you say and that you are in charge. That allows you to keep them safe.
If you make the point when they are 3 or 4 you can be really minimal, one swat. Depends on the kid but if you leave it too long to set the ground rules it is much more difficult and it’s no favor to the kid. They need to understand your expectations. The better your discipline the more freedom you can allow them because they will moderate their behavior right away when spoken to.
My buddy's wife is holding the baby and she would reach up at shining chains or ear rings.
My buddy's wife would gently flick the baby's hand with her finger. Nothing to hurt the baby, just a little discomfort.
A few times of doing it and the baby would stop.
(Lesson learned)
Stuff liked that continued throughout their childrens lives.
They never waited to start discipline.
What you say is quite true, and the reason why my children were well-behaved and reliable upon reaching majority. But that was in a different era,40-50 years ago. But now, if you physically discipline and your child or and observers see and report it, Child Protective Services will remove the child and put you in jail.