Why a verbal agreement isn't enough
California requires a written contract for any home improvement job over $500 in combined labor and materials, and any changes to that contract have to be in writing too.[1]
Even where a state doesn't set that exact dollar threshold, a written contract is what you'll need if a dispute ever reaches small claims court or the bond behind the contractor's license.
What a complete contract lists
Washington's L&I recommends a contract spell out the price and sales tax, a payment schedule and completion date, permit fees when they apply, the exact scope of work, which materials will be used, and who the major suppliers and subcontractors are — with a separate line for what happens if something needs to change once work is underway.[2]
For a siding job specifically, that means naming the exact material and brand, the color, and whether removing and disposing of the old siding is included or billed as its own line item.
What happens when the scope changes mid-job
It's common for a crew to find rotted sheathing or damaged framing only after the old siding is off, and a contract that already spells out a change-order process keeps that discovery from turning into a verbal argument about price.
A reasonable change order states the added cost, gets signed before the extra work starts, and references the original contract number, so there's one paper trail instead of two competing versions of what was agreed to.
Deposits and the payment schedule
A California down payment tops out at whichever number is smaller: $1,000, or a tenth of the total contract price. The only way around that ceiling is if CSLB already has that contractor's Blanket Performance and Payment Bond recorded.[1],[3]
Florida treats a deposit over 10% of the price as the trigger for its own permit-timing rule, so a larger upfront payment there arrives with a deadline attached.[4]
Paying in stages as work is finished, instead of a lump sum upfront or on a fixed calendar, keeps leverage on your side if a job stalls partway through.
The lien warning most homeowners skip past
Washington's required disclosure statement, triggered once a home improvement job reaches $1,000 on a four-unit-or-smaller property, warns homeowners that a supplier or subcontractor who never gets paid can still attach a lien to the property, even after the homeowner has settled up with the contractor in full.[5]
Asking for lien releases from major suppliers as each stage of the job is paid closes that gap directly.
Your right to walk away
California lets a homeowner call off a home-improvement agreement within three days of putting a signature on it, provided the cancellation goes out in writing and is mailed before midnight on the third day.[1]
That window exists for exactly the pressure-sale scenario: a contractor who wants a signature the same day they knock on your door.