If you are an existing client, you do not have to re-list your dependents. Only provide additions or changes to your dependents.
Children who live at your home yet file their own tax returns can create problems if each tax return is not handled properly. For example, if the child claims themselves as a dependent on their own tax return, and you attempt to do the same your tax return will be rejected. However, there might be money left on the table so-to-speak. If your child claims themselves as a dependent, it might not change their tax consequence depending on their income. Yet, this same dependent on your tax return might have a huge impact on your tax consequence- we can provide exact figures for either scenario allowing you to make an informed decision.
You may submit multiple dependents as necessary.