actually the question is far too complicated to answer on a message board.
each state's laws are different. and what may be valid in one state may not be valid in another.
if I am drafting a will for someone who lives in New York I will draft the will according to NY's law. that they later move to Florida does not necessarily invalidate the NY will, but a florida court following florida's probate laws might interpret the will differently than if I drafted the will to comply with florida law.
a power of attorney or health care proxy properly executed under NY law might not comply with the laws of another state. and as a practical matter, the helath care providers in another state might refuse to enforce a health care proxy drafted in NY -- even if it meets the legal requirements of the other state -- simply because it's not from their home state.
bottom line is...if you're permanently moving to another state, it's best to have an attorney from that state look over your legal documents and determine if they're valid in your new home state.