How do I know if a contractor's quote is fair?

Compare against three benchmarks: (1) local $/sqft for your specific project type — pull from regional cost data, not national averages; (2) the labor-vs-materials split — labor should be 40–55% on most renovation work, materials 30–45%; if labor is over 65% the contractor is padding; (3) at least 3 itemized quotes with the same scope written out, NOT 'roughly the same job.' Red flags: an estimate that's 30%+ below the others (you'll pay change orders or get incomplete work), demanding more than 30% down (10–15% is industry-standard), refusal to provide a license number, and any contractor who can't or won't pull the permit themselves.