Business and Law
Licensing is the gate
Contractors are licensed at the state level through the contractors licensing board, and the license requirement attaches to projects at or above the statutory dollar threshold (commonly tested as $20,000), plus any classification the license covers. Bidding or contracting without the required license exposes the contractor to penalties and can bar recovery of the contract price - a favorite trap is assuming an unlicensed contract is a harmless paperwork violation rather than a collection problem.
Contracts, changes, payment
Know the elements of a valid contract (offer, acceptance, consideration, capacity, lawful purpose), the difference between a change order and a constructive change, and the effect of clauses such as pay-when-paid, no-damages-for-delay, and mandatory arbitration. Written notice deadlines in the contract are conditions precedent; missing them can waive an otherwise valid claim. Retainage, prompt-payment rules, and trust-fund provisions govern how money moves down the chain.
Liens and bonds
Mechanic's lien rights run from the last date labor or materials were furnished, not from contract execution or substantial completion. Public work is typically protected by payment bonds rather than liens. Distinguish insurance (workers' compensation, general liability) from bonding (performance, payment).
Traps and rule of thumb
Questions swap the trigger date for a lien, confuse a preliminary notice with the lien filing itself, or mix up who must give notice to whom. Before reading the choices, identify (1) who owes, (2) what deadline, (3) what notice.
Worked example: last day of furnishing is March 14; count the 90-day filing window starting March 15, so the lien must be recorded by June 12. If that date lands on a Sunday, file the preceding business day.