Gradnow

What is everyone doing about state residency if they are moving to a new state for graduate school? I have used my parents address during undergrad and kept my residency here. Is there any advantage/requirement to change my residency when I move to another state for grad school? I will probably move back here when I finish my phd and it just seems easier to keep my license, voter registration, bank accounts, etc here. If you are changing your residency how/when are you going about it?