Always did from day 1. Get them used to it and they will not complain. I started with the Britax B-Agile Travel system,

and now, changed to Britax Advocate.

My own experience, there is no 1 car seat fit for all ages. There will be a compromise in safety and protection somewhere.

In US, the nurse actually comes down and check to make sure the car seat is secured before letting you drive off. No car seat, no departure from hospital.

Also, some countries are starting to state that rear facing car seat to be used till 2 years old.

here is a good video comparing front and rear facing car seats. No imagine a baby with no car seat for those who are willing to risk it.