The laws concerning a legal residence or primary residence may come into play for purposes of insurance, state taxes, and business matters.
Some people have secondary residences, some people choose to remain legal residents of one state while they inhabit another. It can be quite complicated and various statutes may apply, depending on the situation. It can matter for a mortgage loan, for local voting, for healthcare and for business: what is a home?
It can be a place of inhabitance that a person returns, or intends to return, after a specific purpose or job is completed. This could mean that a person spends a few years traveling or living in another place, while still intending to return to a primary residence. A primary residence does not have to be owned by the individual, and it can be shared by others.
A person may have a legal residence and an actual residence which are distinct from one another. The head of a family can legally declare a house and its property to be the legal homestead of a family, and thereby have the property safeguarded from creditors and liens in the event of bankruptcy and so on.
In a nutshell, a home is anywhere you report and can confirm that you dwell, which may be different depending on who you are reporting it to, but, be aware, there are statutes which apply to different situations that may define your home in a different way than you thought, according to their own definition. For ex-patriots living abroad, different statutory residence tests may apply.
If a homeowner attempts to claim a FEMA grant, for instance, for a residence that they attest is their primary residence, but the government determines otherwise, they can be liable for large fines or even time in jail.