So you have Illinois Residency? California? New Jersey? Here is an absolutely incomplete (but good) guide to what you need to think about if you choose to head south from the many high tax states.
Apply for a Homestead exemption in your new state—there is a presumption of residency if the individual is receiving the homestead exemption.
Residency—when an individual is a resident one year they are presumed to be a resident in the following year. If you are present in IL ( or other state) more days than you are present in any other state then you have not changed your state of residency. A good rule of thumb is 6 months and 1 day in your new state.
Location of spouse. Don't leave your loved ones at home.
Voter registration. Make sure to change where you vote.
Auto registration/driver’s license and insurance.
Home ownership. Do you own a home in the new state?
Nature of work assignments in the state. Did your business move? If retired this is moot.
Location of professional licenses need to show the new state.
Location of doctors. This is a one is hard for many but shows that you are absolutely making the move. And don't forget about your vet.
Do you belong to a church? Have a library card? Join a new one and get a new card.
Other important ideas.
Where are your Club memberships? Change the type of membership at your country club or lunch club in your old home state.
Telephone/utility usage. There are stories of states asking for copies of your cell phone bills. These show where you are ( they track what cell tower you are connected to) and are used to verify the move out of state.
Location of organizations to which charitable contributions are given. Think about the local shelter, churches and other places of worship. If you are a resident in a new state then its logical you care about issues in that new state.
There is no guarantee but following these steps help make the transition to your new state cleaner and less stressful.