Grams2five
It’s also entirely possible the needs were always the same but the old advice was wrong.
Yep. Much like everything else, as we progress in education, science, new discoveries are made that make former knowledge obsolete.
The back to sleep is an excellent example. When my eldest was born, I was taught at prenatal classes to NEVER put a baby to sleep on their back, only on their tummy, otherwise they’d choke on spit up.
By the time my next baby was born, it had switched to only on their back, and the rate of SIDS has dropped dramatically.
Car seats are another example. Didn’t exist when I was a baby, now it’s law.