“No one walks down the aisle with a pacifier in his mouth.” “College admission offices aren’t going to ask how old she was when she was toilet trained.”
The above (one hopes) true statements are relayed to young parents as a way of saying, “Relax.” As such, they are valuable bits of advice from those whose children are older and who recognize that things that mattered greatly at one point became completely irrelevant down the line.
Not everything falls into this category, of course. Sometimes, things that happen in one’s early years have grave repercussions down the road. A mother who drank heavily or took drugs while pregnant may damage her child in a way that no later intervention will be able to correct. A baby deprived of sensory contact, affection and security might need to struggle mightily in future decades in order to live a happy life. These examples are extreme, but good people recoil at the not-so-uncommon scenario of a child given sugar as a major food group or one who is plopped in front of a screen for hours a day.