@b-bbwgirl , not knowing in ref. to what , it is only a guess below --
(a) for purposes of form 1040 or the state filings , you use the latest address -- that is where you would receive your refund ( if checks ) and/or any notifications from the IRS and/or the State
(b) for purposes of homestead credit ( in states like MI ), you show first the newest address and then the earlier address as a renter or as a home owner
(c) for school district purposes , you have look at the state instructions , but generally you have to report both , most recent first and then the older one .
Hope this helps