In the United States, obtaining a certificate is generally required whenever: The purpose of obtaining a certificate of occupancy is to prove that, according to the law, the house or building is in liveable condition.
A certificate of occupancy is evidence that the building complies substantially with the plans and specifications that have been submitted to, and approved by, the local authority.
In New York City, TCOs are usually active for 90 days from the date of issue, after which they expire.
[2] It is perfectly legal, and not uncommon in the given situation, for a building owner to re-apply for a TCO, following all the steps and inspections required originally, in order to hypothetically extend their TCO for another period of time.
Temporary certificates of occupancy are generally sought after and acquired when a building is still under minor construction, but there is a certain section or number of floors that are deemed to be habitable, and, upon issuance of TCO, can legally be occupied or sold.