What a state test typically requires, and why physical presence alone rarely settles it. State statutes generally combine a durational element with an intent element. California is a compact example. Education Code section 68017 defines a resident, for tuition purposes, as "a student who has residence pursuant to Article 5 (commencing with Section 68060) of this chapter in the state for more than one year immediately preceding the residence determination date", and section 68061 provides that "every person who is married or 18 years of age, or older, and under no legal disability to do so, may establish residence". The intent element is in section 68062(d): residence "can be changed only by the union of act and intent". That is what stops the clock starting on arrival alone, because the year has to be a year of residence rather than a year of presence, and an institution's residency office is entitled to look for evidence of the intent as well as the dates. California also settles the question for a student who is still a minor: under section 68062(f) the residence of the parent the unmarried minor child lives with is the child's residence, and under (g) it "cannot be changed by the minor's own act". Where a student is under 18, the question is therefore where the household is, not where the student is.
The military and Foreign Service override, and the part people miss. Section 135 of the Higher Education Act, at 20 U.S.C. 1015d(a), provides that where a member of a qualifying federal service has a "domicile or permanent duty station" in a state receiving federal higher education funds, the state "shall not charge such member (or the spouse or dependent child of such member) tuition for attendance at a public institution of higher education in the State at a rate that is greater than the rate charged for residents of the State". Subsection (d) covers three categories, each requiring service of more than 30 days: a member of the armed forces on active duty, a member of the Foreign Service, and, added in December 2023, an officer or employee of an element of the intelligence community. The part most often overlooked is subsection (b), the continuation rule: once the rate has been paid, it "shall continue to apply to such member, spouse, or dependent while continuously enrolled at that institution, notwithstanding a subsequent change in the permanent duty station of the member to a location outside the State". A reassignment mid-degree does not reset the rate as long as enrollment is unbroken.
The GI Bill override works by a different lever, and knowing which lever matters. 38 U.S.C. 3679(c)(1) does not give the student a right to a rate. It requires the Secretary of Veterans Affairs to "disapprove a course of education provided by a public institution of higher learning" if the institution charges covered individuals pursuing that course with chapter 30, 31, 33 or 35 benefits, or chapter 1606 of title 10, "while living in the State in which the institution is located", more than "the rate the institution charges for tuition and fees for that course for residents of the State, regardless of the covered individual's State of residence". The consequence for a non-compliant college is loss of VA approval, which is why it works. Three qualifiers travel with it. The covered individual has to be living in the state where the institution sits. Paragraph (c)(3) extends the protection to later courses at the same institution while the individual "remain[s] continuously enrolled". And paragraph (c)(4)(A) preserves the institution's ability to require the individual "to demonstrate an intent, by means other than satisfying a physical presence requirement, to establish residency in the State", or to satisfy other non-residency requirements, without triggering disapproval.
Why the rate reaches further than the tuition line. A public college's cost of attendance is built from what it charges that student, so the resident rate flows into every figure downstream of it, including the need calculation. It also decides which published numbers describe a student at all. Under 20 U.S.C. 1015a(b)(1) the Department of Education calculates a public institution's cost of attendance, net price and tuition and fees for first-time, full-time undergraduates "who are residents of the State in which such institution is located". So a public university's published net price is a resident's figure, and an out-of-state applicant reading it is reading a number about somebody else. Running that college's own net price calculator is the way to get one that reflects the non-resident rate.
The status has adjacent consequences worth separating from the tuition question. State grant programs commonly have their own residency requirements, which are not necessarily the same test as the tuition one. Federal student aid runs on a different footing: the eligibility conditions at 20 U.S.C. 1091(a) turn on enrollment, satisfactory progress, citizenship or eligible immigration status and the like, and say nothing about which state a student is a resident of. So a student paying the out-of-state rate has the same federal eligibility as a resident classmate, applied against a larger cost of attendance.