My friend (I don't know him in person, we work together remotely) told me that he has 3 cell phones: one at home, one at the work-place and one always turned-off in his car (for emergency). He doesn't wear a cell phone with him. When someone wants to contact him he/she calls him on one of his home/work phones judging from the day time, if he doesn't answer the call he calls back when he reaches home/work place and sees unanswered calls.
Two years ago when he told me this I thought he is a tinfoil-hat paranoid person but now I know he is right.
He's not being paranoid enough. A guy with a cellphone that never leaves the home? Any decent data analysis software should flag such an odd behavior. If one's not willing to fully disappear off the map, the safest behavior is to provide "boring" data in order to blend in with the crowd.
But if you hang out just a little bit with pot heads in eastern Europe you know the best solution is to turn off your phone and take the battery out when you don't want people tracing you or lightening to your conversations.
Two years ago when he told me this I thought he is a tinfoil-hat paranoid person but now I know he is right.