The move changes the rate; the record decides whether it sticks. New York keeps taxing until domicile actually changes — clear and convincing evidence, and its 183-day statutory test stays live while any New York abode is maintained. Below: what follows leavers, and the Florida steps that build the record.
Who has to show it: on the party asserting the change of domicile; intentions are weighed against unequivocal acts.
183 days · any part of a day counts
No test
IT-203 (part-year)
No income tax return
At New York's top marginal rate (10.9%), every $100,000 of taxable income is $10,900 of state tax — an illustration at the top bracket, not an effective-rate calculation. Official rate tables are linked below.