Fron DOC website:
QUOTE
1. The Concept of Usual Residence
The Census Bureau's enumeration procedures are guided by the constitutional and statutory mandates to count all residents of the several states. [U.S. Const. Art. 1, Section 2, cl.3, Title 13, United States Code, Section 141.] The state in which a person resides and the specific location within that state is determined in accordance with the concept of “usual residence,” which is defined by the Census Bureau as the place where a person lives and sleeps most of the time. This is not always the same as a person's legal residence, voting residence, or where they prefer to be counted. This concept of “usual residence” is grounded in the law providing for the first census, the Act of March 1, 1790, expressly specifying that persons be enumerated at their “usual place of abode.”
Determining usual residence is straightforward for most people. However, given our nation's wide diversity in types of living arrangements, the concept of usual residence has a variety of applications. Some examples of these living arrangements include people experiencing homelessness, people with a seasonal/second residence, people in group facilities,[2] people in the process of moving, people in hospitals, children in shared custody arrangements, college students, live-in employees, military personnel, and people who live in workers' dormitories. ENDQUOTE
My Opinion: However, with a population of over 300 MILLION, I seriously doubt anyone will be knocking on your door to explain your census answers.