Avoid NSO......easy, but somewhat "old school"....(see "burner phone")
1. Buy a mobile which is not a smart phone (say a 3G feature phone).
2. Go to a convenience store and buy a pay-as-you-go SIM for cash (say Lebara)
3. Go to a different convenience store and buy lots of minutes for cash.
4. Register the SIM and the minutes in a public place, a place not usually associated with the rest of your life.
5. Have the phone switched off most of the time.
6. Only switch the phone on in a public place, and only for long enough to make calls or respond to text or voicemail.
7. Persuade people close to you to follow steps #1 through #7.
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This process (pretty much) guarantees that ANYONE snooping on your phone traffic has NO IDEA about your identity.
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Of course, if your social network includes individuals who are not very careful, then your mileage will vary. But of course, you can always start again at item #1.....!!!!!