New York Residency Audits for Snowbirds

New York aggressively enforces its residency audit program.  New York residents must pay income tax on all income, and estate tax on all assets.  A non-New York resident pays income tax only on New York source income and pays New York estate tax only on New York situs assets.  A typical audit case might involve a person who is domiciled in Florida but maintains an apartment in New York and travels to New York for work and/or pleasure.

The test for residency is different for income and estate tax purposes.  For income tax purposes, a person is a New York resident if he meets one of two tests.  ​

The first test is domicile. A person’s domicile is his primary residence. It is the place the person would live if he could only have one home.  The determination of domicile looks to five primary factors: (1) the home factor, which is a comparison of the person’s home in New York versus his home in other jurisdictions, (2) the business factor, which is a comparison of the person’s business contacts in New York versus his business contacts in other jurisdictions, (3) the time factor, which is a comparison of the time the person spends in New York versus the time spent in other jurisdictions, (4) where the person keeps his financially and sentimentally important items, and (5) a comparison of where the person’s family members are in each jurisdiction.

There are secondary factors as well, such as where the person’s drivers license is from, where the person is registered to vote and where the person’s cars are registered.

The second test for income tax residency is a statutory test.  It is based upon the number of days spent in New York. Under this test, a person is a New York resident for income tax purposes if he has a permanent place of abode in New York and also spends more than 183 days of the year in New York.

There is a single test for residency for estate tax purposes.  That test is the domicile test.

Sources: 
Income tax definitions - Department of Taxation and Finance
To Avoid NY Statutory Residency Traps: Go By The Rules, Not - Forbes