Jobs under $30,000 inc GST
If it is your standard method of business, you can ask the homeowner for a deposit. We would advise against asking for large deposits up front as this can make homeowners nervous that they will be left out of pocket with uncompleted work.
Jobs over $30,000 inc GST
Jobs valued over $30,000 including GST require a written contract and you may require a deposit. Deposits are usually 10% of the job price.
We would recommend reading over the requirements on the Consumer Protection site.