This is how the state of Michigan views it. Taken from the MI-1040 Individual Income Tax Forms and Instructions.
https://www.michigan.gov/documents/taxes/BOOK_MI_1040_674612_7.pdf#Page=6
Resident
Resident. You are a Michigan resident if Michigan is your permanent home. Your permanent home is the place you intend to return to whenever you go away. A temporary absence from Michigan, such as spending the winter in a southern state, does not make you a part-year resident.
