As of now, Australia's telecommunications service providers have to store your metadata — records of your phone and internet activity, which can reveal a huge amount of detail — for two years. Approved government agencies can access that data without a warrant. It's not private information, either.
One way to circumvent Australia's draconian metadata retention scheme is to install and use a VPN on your phone and on your PC. Here's what a VPN is, what it does, and why — and how — you should get one.