Interesting thread. In my experience, my oldest friendships- made in childhood were/ are special but, they weren't necessarily my best. There's really only one friend I keep in (irregular) contact with from way back then- I'm 45.
My deepest friendships were made at uni though so- aged 18 first time round. 28 the second. For me, I tend to gravitate towards other creative people. Creative people are often obsessed about their work. A lot of their worries revolve around their work- even, not having that work.
It's not something I've found other people really understand. Because it is pretty abnormal I guess! But, I suppose- seeing as friendship I believe in large part is about trying to find support/ understanding/ to fulfil a need, the need to be understood for worrying like hell about some project say- other people who are the same way can simply relate better- in my experience.
So- it probably depends what an individual needs. I care about my longest term friend. I especially value them because they were with me when I went through what made me suicidal to begin with. So- they have that understanding that really, no one else does. And, kind of vice versa too- they were struggling at the time too.
It can work in reverse of that though too. It's only really that this person always supported me that we do still keep in touch. Overall- my school years are ones I'm keen to forget. So- asides from them, I've actively tried to avoid friends from that period. In making new friends at college/ uni- the hope was to put that time behind me. So- I also think it depends on how you view your life. Whether you want to remember your childhood or not!
I tend to see online friendships as different to IRL ones. Which is kind of weird because by now, I've likely shared just as much with online friends. I suppose I wonder if we can really know each other though. Not that I do see people face to face much now. I try to avoid it but, there are so many other nuances we pick up by being around one another. I don't think I would have had the depth of friendship I've had with my better friends if we hadn't known one another in person. It just gives you more to love I suppose. Maybe I'm just old fashioned though.
I'm not sure time spent has much to do with intensity of friendship though. I've felt very strong connections with some people almost from the off. I think we just click with some people more than others and we can sometimes realise that really quickly.
Maybe there isn't the back history knowledge on one another but again- that can be good- if you are trying to move on from that part of your life. We exist only in the present anyway so- what we're feeling right now is probably enough to go on. Either people will relate to and care about that or, they won't.
