The answer
Must be a written, fixed-price contract with: full legal contractor details/license number; itemized scope with architectural plans and specific material model numbers; start/completion dates; progress payment schedule tied strictly to completed phases; statutory 3-day (or 5-day for seniors 65+) right-to-cancel notice; Mechanics Lien Warning; and written change order clause. Down payment limits: In states like California (BPC 7159), deposits are strictly capped at 10% of the contract price or $1,000, whichever is less.
Sources
This answer is drawn from the standards and guidance below. It is general information about how these systems work — not a diagnosis of your property.