How New York Hunts Down Tax Refugees

Every year, some 55,000 New Yorkers move to Florida, more than those who migrate to any other state. In addition to year-round sunshine, ex-New Yorkers also get relief from some of the country's highest state taxes. And while academics disagree on just how much taxes influence moving decisions, studies show taxes especially sway retirees and other folks living off investment income. According to the AARP, more than half of New Yorkers over age 50 who are planning to retire said they're considering leaving the state.

New York is not taking this lying down. Few states are as strict about residency rules, accountants and attorneys say, which means that if New Yorkers want to leave–and take state tax revenue along with them–they must prove they really are gone. Each year, New York's Department of Taxation and Finance collects more than $200 million from "residency audits," in which taxpayers must provide elaborate evidence of their whereabouts.