A contract is the written record of what was agreed. Its purpose is not distrust; it is that memories of a conversation weeks earlier genuinely differ.
What it should cover
The scope of work — what is included, excluded and assumed.
The price and how it was arrived at, and what happens if the work changes — see change orders.
Payment: deposit, stages, and terms on the balance.
Timing, and what happens if either side causes a delay.
Warranty: what is covered, for how long, and what voids it — see warranties and guarantees.
What happens if either side wants to stop.
The clauses that matter when things go wrong
Which law applies and where a dispute is heard.
Whether disputes go to arbitration or to court.
Whether the losing side pays legal costs. Without this clause, recovering a small debt frequently costs more than the debt.
Consumer protection applies to residential work
Home improvement contracts are regulated in most states, with requirements on written terms, cancellation periods, deposit limits and specific disclosures.
These are not optional and are not general good practice; a contract missing a required term can be unenforceable, which removes the protection it was written to provide.
Signature
Before work starts. A contract signed afterwards is a record of a dispute rather than a prevention of one.
Electronic signature is generally valid and is materially better than nothing.
Getting one
A template reviewed once by an attorney who knows the trade and the state, then used consistently, is the practical approach. Contracts assembled from the internet routinely omit the state-required terms, which is the part that actually matters.