Part Year Residency: Records to Keep From Day One

New York's part-year tax return does not ease into the subject. Item G of Form IT-203 reads: "If you were a New York State resident for part of the year, enter the date you moved." One field. A specific day, month, and year — for something that, in real life, took nine days, two cars, and a mattress that spent a week on a friend's floor. The return will ask next spring. The evidence for the answer exists now, this week, and most of it is paper you are about to throw away.

Checked: 3 September 2026 against the sources linked in each row and paragraph below — the 2025 IT-203 instructions on tax.ny.gov, FTB Publication 1031 (2025) and the 2025 Schedule CA (540NR) on ftb.ca.gov, Virginia Tax's residency page and Form 760PY, Colorado's part-year page, and Wisconsin Publication 122 with the 2025 Form 1NPR instructions. Forms are revised every tax year and pages move. Before you rely on a line number or a quote, open the linked page and confirm it. Nothing here is tax advice.

An interstate move usually means two part-year returns: one to the state you left, one to the state you arrived in. Each side asks for its own copy of the same facts. The state you left wants to know when you stopped being its problem and whether you really stopped. The state you arrived in wants to know when its meter started. Neither question can be answered from memory in April, and both are answered easily from a folder you can start today.

Every part-year form has a date field, and some have four

Here is where the date actually goes, state by state. Notice that California wants the day you arrived and the state you came from — the departure side and the arrival side printed on the same line.

Two things in that table deserve a second read. Virginia's boxes are per person — if your spouse stayed behind to close out the old house for six weeks, the state expects two different date ranges, not one. And California's line 6 is not a date at all. It is a count: days present in the state for any purpose, which nobody can produce in April without a calendar kept at the time.

Wisconsin wrote down exactly what a state wants to know

The 2025 Form 1NPR instructions end with the Legal Residence (Domicile) Questionnaire, form I-151, and it is the most useful document in this entire subject — not because you will necessarily file it, but because it is a state revenue department showing you its actual list of questions. Eleven of them, nearly all demanding a date:

• On what date did you move? Did you intend to move back, and when?
• After establishing residence in the new state, list the dates you were in Wisconsin — and, separately, the dates you were physically present in the new state
• Did your spouse and dependent children move? When?
• On what date did you begin working in the new state? Was the job permanent, temporary, or seasonal?
• In the new state, did you register to vote, buy a home, obtain a driver's licence, register a vehicle, file resident returns — and when, or if not, why not?

Then comes question 8, which I think of as the backslide list. Since leaving, have you renewed Wisconsin plates? Renewed a Wisconsin licence? Voted in Wisconsin, in person or absentee? Sent your children to Wisconsin schools? Bought a resident hunting, fishing, or trapping licence — and in which county? Every item is an act that quietly contradicts the move date you wrote in question 1. The form closes with a warning that the return "may be returned to you or its processing delayed if the questionnaire is not completed."

The asymmetry is the lesson. Someone moving into Wisconsin checks a single box — changed legal residence to Wisconsin from a named state on a named date — and is told to skip the rest. Someone moving out answers everything. Your arrival state mostly wants a date. Your departure state wants the story, with receipts.

The folder, mapped to the questions

So build the folder on day one, while the paper still exists. Five compartments cover every question above.

The move date itself. One dated, third-party document that fixes the day: the lease with its start date, the closing disclosure, the moving company's delivery paperwork, the truck rental return receipt, the utility connection email. Screenshots count. On my second move I could not have named the day within a week of it — the answer turned out to be sitting in a power company email I nearly deleted.

A day log. California's line 6 and Wisconsin's questions 3 and 4 are lists of days, not a single date. A calendar note each time you cross back — funeral, closing, one last load in a borrowed van — takes ten seconds per trip. Reconstructing the same list in April from fuel receipts takes an afternoon and still has holes.

The DMV chain, with receipts. FTB Publication 1031 lists the factors California weighs: where your driver's licence was issued, where your vehicles are registered, where you are registered to vote, where your banks and your doctors and your professional licences sit. These are the same errands that already carry legal deadlines in your first month — the extra step is keeping what the counter hands you. The licence receipt showing the date of issue and the surrender of the old card does double duty; it is also factor evidence in the domicile record, where a relinquished licence counts separately from a new one.

Household dates. When the spouse moved, when the kids changed schools, the offer letter with a start date. Wisconsin asks all three by name. Virginia prints separate date boxes per spouse.

The old house. Wisconsin's question 10 asks whether you still own the home you occupied there, whether you disposed of it, when, and what use you make of it now. California's line 7 asks about property with a Y or an N. Keep the listing agreement, the sale closing, or the management contract that turned it into a rental — whichever one describes what actually happened.

Where the folder stops

Be clear about what this folder does and does not settle. New York's nonresident FAQ sets the standard a departure state can apply: your domicile "does not change until you can demonstrate with clear and convincing evidence" that you abandoned the old one and established a new one — and, pointedly, "it is not enough simply to file a certificate of domicile or register to vote in the new location. All aspects of a person's life are considered." Virginia adds a tripwire on the residency status page: move out and return within six months, and as a general rule you have not demonstrated intent to establish residency anywhere else. The folder is how "all aspects of a person's life" gets answered with dates instead of adjectives.

What the folder cannot tell you is which income lands on which return, or how either state divides a year of wages. That is a genuine tax question, I am not a tax preparer, and this is the line where this site stops. The starting points are the two pages your states wrote for exactly this situation — the part-year guidance linked in the table above for the state you can see out the window, and its counterpart from the revenue department of the state you left.

Tonight, before the moving boxes bury it: photograph or file one document that carries the move date — lease, closing sheet, delivery receipt, utility email — and start the day log with a single entry. That is the whole day-one job. Everything else in the folder accumulates on its own, one counter receipt at a time.