If the carrier is your main threat, then port your number out to Google Voice, lock that down seriously, and go prepaid. If you buy your phone in cash, install

If the carrier is your main threat, then port your number out to Google Voice, lock that down seriously, and go prepaid. If you buy your phone in cash, install a privacy-sneisitive OS like Graphene, and only use prepaid without giving info, then your phone starts off as being not associated with you. From there, you need to practice extremely good hygiene to not have it tied back to you. Never give anyone that phone number (only use the Voice number, which you'll forward), only connect by VPN, probably use few or no apps (web apps only), and definitely never have your phone on outside of a faraday bag within, say, 1 mile of your house (distance depending on density.) There are legitimate reasons for doing this (one great example is to never get caught unwittingly in a geofence search warrant), but mostly it's not worth the trouble. And that's why no one does it. All this to say that you should treat all the info you give to telcos as leaked from that time, and act accordingly. The only way to seriously avoid leaks is to give them nothing to leak.