In this mobile society, oftentimes, former spouses or never married parents leave the originating state to start a new life. In the absence of children, alimony, or a pending property division settlement, the exes may never see each other again.
However, when parents move, two states may have jurisdiction on pending matters. For example, a New York court may have jurisdiction for child enforcement matters, but a Georgia court may have jurisdiction for changes in custody/visitation.
In those cases, it may be better to find an attorney who is licensed and practices in both states. Indeed, in my practice, I often receive calls from mothers and fathers who live in Georgia, but have open or prospective cases in Maryland or New York or vice versa. In those cases, I can easily educate them on their rights and represent them in the state of their choice.