Reflecting on my own experience - frequency of contact (if I see them once a year, can't really count them as close friends) How involved they are in my life - are they people I turn to when I'm facing a problem, do they turn to me when facing their own problems? Do we have frequent deep conversations - not just surface level discuss the weather, sports etc. but stuff that matter. Quantifying this - length of friendship (# of years), frequency of contact (annually, monthly, weekly etc.), level of trust (low, medium, high - can I trust my kids with them kind of trust), level of involvement (low, medium, high - what things do I feel comfortable sharing with them - suppose this is also level of trust?)
>> Reflecting on my own experience - frequency of contact (if I see them once a year, can't really count them as close friends)
I think this one is interesting. If you saw them daily for 20 years and then transitioned to once a year are they automatically not close friends? Even if they satisfied the other criteria (like you could turn to them when you are facing a serious problem, you have deep conversations on that annual meeting because you are comfortable with them, etc)?
I'd say we need a more analog definition than a binary one.
The term 'close' friend at least to me means close. Either in physicality or depth and regularity of contact.
Only talking to them once a year, even in depth is more like a semi-close friend. They are not there to help you with the day to day issues that you may not even realize you're having.