My phone is permanently on silent unless I have agreed that you can call me.
I can't imagine wanting things any other way. I'm all about pull notifications not push.
This works fine in principle, but in practice about 85% of people I (grudgingly) want to receive a phone call from are large bureaucratic organisations like the NHS who call without warning from a withheld number.
Ah yes, but I don't get unsolicited calls from the NHS. I generally know they're going to call, because I've had to chase them to do so.
In addition to that, they tend to phone me up out of the blue to say that the GP's computer wants to see me to check I'm still asthmatic, or would I like a vaccine or something. Though I've noticed they're increasingly using SMS for that sort of thing (which is just sensible - why waste staff time when the computer can just get on with it). Not foolproof though - the orthopaedic hospital's systems have been designed by someone with limited imagination, so you tend to get vague messages (in various media) telling you to call "the hospital" about "your procedure", as if people don't have arms *and* legs.
Meanwhile, we've been waiting a week and a half to hear from a gas man. Barakta got a spate of calls she couldn't answer a few days ago from assorted mobile and Bradford numbers, but we're reasonably sure that wasn't it, as we're nowhere near Bradford.