The following link has both a summary of what type of business requires a privacy policy and a step by step questionaire to help you decide if you need a privacy policy.

Handy if you have ever wondered if you need one on your website.

https://www.oaic.gov.au/about-us/our-corporate-information/key-documents/privacy-policy/

I don't believe my business needs a privacy policy page. But I do have what I call privacy principles that I feel are good to live by both professionally and privately.