You have many more choices than just signing your builder's contract.

Never feel pressured to sign. If you're planning to pay for any building work in Australia, there are laws to protect you, but remember once you have signed, you have obligations.

It's important that you understand the risks, obligations and responsibilities. If they are not clear to you, please, please take the time to seek advice.

Every building & renovations contract you sign must, by law, comply with certain minimum requirements. They key word here is minimum, and that's often not enough.
Each state and federal government in Australia have been in an ongoing battle with the building sector to set basic consumer protection mechanisms in place, but you still have the sole power to decide what type of contract should be used, and what terms that contract should contain.
If you're about to embark on renovations, you should be aware that the States have different dollar amounts before a written contract is legally required, although we recommend every and any bit of building work being paid for by you, should be set out in even a simple contract.

In New South Wales, any building work greater than $1,000 requires a contract, while in Queensland it's $3,301. Finally in Victoria, a contract is normally necessary for most renovation work greater than $5,000.

Builders understandably want you to sign a contract that suits them, but unhappy outcomes & disputes result from customers' contract ignorance.
The vast majority of contracts used by builders and tradespeople around Australia are provided to them by the Master Builders Association or the Housing Industry Association. These groups work for and represent the builder. That's their job.
Their contracts are for the most part very good. Many buyers are unaware that these contracts are also templates that allow many common clauses to be inserted or removed. Many of these clauses are up to you to know about.
Understanding building contracts before you need them is a great way to prepare for getting quotes. It can help you prepare a detailed brief of your project for contracts to quote on and help you negotiate prices after you have received your initial quotes.

If your contract does not include these points, your builder knows it's useless and illegal.
What are the minimum legal contractual terms for residential building work?
The contract must be in writing in clear English and must:
Set out in full all the terms of the contract
Give detailed descriptions of the work to be carried out
State the names and addresses of the parties to the contract
State the builder's registration number as it appears on the builder's registration certificate
State the contract price
State the amount of the deposit and progress payments as required by law
State the date the contract is effective (the date on which both parties have signed the contract)
Give clear advice about the five-day cooling-off period
Include definitions of words and key phrases used in the contract