All of my boys have been to chiro after birth. Eldest not until he was 2, but with my second child he went at around 4 months, he had a horrible horrible cough which the Dr's just ignored. Went to Chiro, he had issues with his neck and shoulder relating to birth and they also advised me to use only lactose free dairy and his cough dissapeared.
My youngest son went at around 6 weeks. He has probably had the least amount of adjustements but I don't know if that's because he went earlier so they caught onto things quicker.

We tend to go every 6 months unless I feel they need to be seen earlier. Where I am in Vic we use a group called Kiro Kids, they are fantastic and I really like the method that they use.