I am part of a group of friends spread around the world - we keep in touch regularly, we help each other when one is in need ... but I do not share my secrets with anyone and would not expect to share those of others.

we're lucky if we have 2 or 3 really good friends in our lifetimes.

I have 2 best friends, one female colleague from uni whom I still keep in touch with and the other best friend is my boyfriend. These 2 people I fully trust. They never criticize me and I can be myself around them. They love me despite my imperfections. I am so grateful to have them in my life.

Best friends help a lot in dealing with life and circumstances

Best friends? Yes I have them. I always have. Usually just 1 or 2.

And the first one I had I grew apart from - and that's okay - it never occurred to me she's turn on me? Thank goodness. My friends have never been like that.

Choose friends wisely and they never will be - even if something comes between you - you'll still share those same standards that would never allow you to break those friendship ties. (That's ugly).

I think as you age it's more likely that distance or life changes push you apart. And you shouldn't worry about them turning into blackmailers if you chose wisely to begin with.
(I doubt I have much worth being blackmailed about!).

Yes

I had best friends in childhood, like all children do, then in my 20s and 30s I became more cynical about the world and didn't trust anyone enough to tell them "things you would take with you to your grave" for the exact reason you mention.

However, in my 40s I made a friend at work and we immediately felt strong kinship, which meant we got to know each other very well very quickly. If I believed in fate, I'd say we were meant to meet and be friends, because even without either of us meaning to share all our deepest secrets, longings and desires came out in conversations over the course of time. I trust her with mine even more than I trust myself, and I know she trusts me in the same way otherwise we wouldn't have had those conversations.

I'm still cynical and still don't trust the majority of people, but experience permitted me to realise I had a true best friend in her.

I guess for me too best friends were important when I was younger but now I don't even care about having friends. Lately, at most I see my closest friends in person may be just a few times a year. I keep up with them online and that's enough for me. I prefer to be alone and avoid other people's drama. I live pretty isolated from other people so it's easy to be the loner/hermit that I am. I don't feel the need to have best friends, or friends even, for that matter.

I lost all my so called best friends over the years..people change or the big one they don't change. My current so called best friend is more like a frenemy....he stresses me out for sheer entertainment...

I agree with you. I do sort of have a best friend but we argue also and he is a believer that I've known for over 50 years. There is no way that I would "tell him everything." I simply do not trust people. Nobody needs to know innermost things about you and if you tell some things you are simply setting yourself up. When it comes to women I don't need to know that you were once owned by Chez and made porn movies. Well, maybe if there is a chance I might watch one and see you. I don't need to know of any BF before me coz it does not matter. I once had a GF in Texas who declared that now I had to tell her everyone I had had sex with. I'm sorry. You're wrong! This "best friend" thing gets out of hand. Some people even want to discuss bowel movements. It's not for me.

I was bereft when I lost my best friend and confidante in 2016...she and I were closer than sisters. She was my bulwark when I lost my husband and I could use her as a sounding board on any subject...and she with me, in complete confidentiality and honesty. She would have told me if I was wrong or ridiculous (yes even I can be that sometimes!) My relationship with her was different from that of other friends, some whom I can confide in, but not to the same degree, and I miss her to this day, and especially recently when I lost my son. Luckily I do have other very good and supportive friends, but Bonnie was a once in a lifetime friend, a bit like my husband Peter was my once in a lifetime love.

I can't remember ever having a friend I could trust. I'm sure it must be a great thing psychologically so I hope it actually is a thing.

Friends come and go. You will change and so will they. I made the mistake of allowing
really crappy people to come into my life. Now that I'm older I have friends that I have complete trust in. They are out there. I got lucky and found four couples that are great friends, liberal, non religious and I am single.
So, find GOOD friends and try to manage and distance from the bad ones. If they do wrong to another, they will eventually do it to you. So, judging your "friends" is a continual process. Its for your own survival. (From an older person).