How old does a child have to be to decide which parent they want to live with in nj

18.

A child is not allowed to decide. His opinion MAY be taken into consideration by the judge but ultimately it is up to the court.

So what you are saying is he can't decide until he is 18 a court has to decide... he wants to live with his father because I smoke and he has asthmatic bronchitits and I am a functioning alcoholic... I do not drink during the day, but he has seen me tipsy at home during a friendly card game on few occasions, I have never put him or my family and finances in harms way, I am a good mother and do not want to lose him...

Unfortunately, by your own admission in the above statements, his father has a good chance of getting primary custody if he pursues it. Your idea of "never putting him in harm's way" will be different than the court's idea of "harm's way." As another poster stated, he really doesn't have the choice himself until he is 18, but the older he is the more weight the judge will give to his stated preference. If your smoking in the face of his health issues is what's prompting him to say "I want to live with my dad", that's probably all the judge needs to hear.

You smoke and he has an asthmatic condition and you call yourself a good mother?

I doubt a court will agree with that.

Its true that he cannot make a unilateral decision, but given the circumstances you state, I tend to think the court will see things his way.