We have a number of sitters benefiting from additional income they have earnt pet sitting, but it is important to manage your business affairs properly (this means lodging any reporting and payments on time to the ATO and keeping good records if applicable).
From information available as at 1 June 2016, whether you need to set up a business depends on how much you intend to earn. If pet sitting remains more of a hobby, then you may not need an ABN. But if you plan on "carrying on an enterprise" providing pet sitting services through a sharing economy app or website (such as PetCloud) then you will need to get an ABN.
See the ATO's website if you have questions about whether you are just doing a hobby or whether are running a business. If you are running a business, you will also need to register for GST if your turnover is, or is expected to be, $75,000 or more per year.
Refer to the ATO website or you may wish to call them on the Personal Tax Info Line 132 861 or the Small Business Info Line: 132 866. And if in doubt talk to your accountant or a tax expert. And remember by using PetCloud you can keep all your receipts in one place, helping you manage your business simply and carefully.
Don't just go to your friends for tax advice, and don't feel overwhelmed or intimidated by tax jargon, the ATO info line is for everyone and they are patient, helpful, and friendly. So don't leave questions until the end of the financial year.