How old does a child have to be before they can decide where they want to live?

How old does a child have to be before they can decide where they want to live?

What are circumstances please. Do you live with mother and want to live with father for instance. Do you wish to be emancipated from your parents?

They have to be 18 in almost all states, a couple allow it at 17.

To move from the custodial parent to another parent before that, takes a modication of the court order. So the parent who does not have custody that wants the child will have to file a motion in court, the child can testify but the court will look also at other factors