The judge will consider any factor that is relevant to promoting the best interests and welfare of the child. While an exhaustive list is impossible, some important factors a judge will consider are: which parent has been the primary caregiver for the child; does either parent have alcohol or substance abuse problems; which parent can provide the most stable living arrangement for the child; which parent will best promote a close, loving relationship between the child and the other parent; and the parent’s availability to care for the child.