Tennessee's Notice of Commencement under § 66-11-143 is the trigger for the state's strict 90-day Notice of Nonpayment requirement. Once recorded, remote contractors who don't serve a timely Notice of Nonpayment can lose their lien rights — a major protection for owners and primes. Required for projects with a total contract amount of $25,000 or more on commercial property; optional but commonly used on smaller projects. The owner or the prime contractor (in practice, often the prime contractor) records the Notice of Commencement. Within 30 days of commencement of the work, but recording before work begins is the safer practice. With the Register of Deeds in the county where the real property is located.