You see, our parents NEVER did that. They never second guessed themselves. And that was cross - class too - the working class never questioned themselves, nor did the upper classes.
Hmmm...
This is the disadvantage of growing old: you remember that lovely past when everybody supposedly had all the answers.
From what I can remember, my mother struggled with the continuous angsting of her MIL over every aspect of child-rearing, though especially anything involving hygiene. You didn't have to listen to my grandmother for very long to realise that a) her son had been the Only Child on the Planet Ever b) she had angsted as much as a mother, bringing him up, as she did as a grandmother. NO idea how my dad turned up as sane as he did.
My MIL once told me that they moved away because the constant fussing over their son by her MIL was turning him into an anxious little boy. Round about 1960 that would have been.
Child-rearing books have a long history. Made fun of in the Anne of Green Gables books (written in the early 1900s). Dr Spock, at a later date, didn't write his books because all parents knew exactly what they were doing and never questioned themselves: he wrote them because he was surrounded by anxious parents who wanted reassurance.