Different people might use it different ways, by my tiers would be;
1) critical: My elderly parents, my daughter, and a few other family and close friends who always have my ear
2) family and friends: basically people who are part of my social life I'm generally happy to hear from
3) work: people I work with or predominantly talk to about worky stuff. No offence to anyone, but I'd like to be able to be 'away' for these people when I'm off the clock and relaxing
(2/3)