After a certain age, friendship is expected to play "second fiddle" to our other relationships, says journalist Julie Beck, but this needn't be the case.
She spoke to 100 sets of friends actively maintaining their friendships in creative ways for the popular Atlantic column The Friendship Files.
This year, after three years, Beck closed the column, but not before writing an essay about what she'd learnt.
She talks to Jesse Mulligan about the six keys to life-long friendship.
What's so unique about friendship is we have no cultural script for it as we do with our other relationships, Beck says.
"With romantic relationships, there's very much a script, and you don't have to follow it but even if you make different choices you're still resting to that script we all know.
"Friendship [by contrast] has to be designed from within. The friends have to choose what their friendship is going be like, how often they're going to see each other, the role that they play in each other's lives. That's beautiful but it can be daunting.'
It can also be a daunting subject for men to talk about, Beck says, whereas women seemed more used to speaking about the role it played in their lives.
"Our culture minimises male friendships to a degree or stereotypes them, like they're [only] about sports and activities… but the men that I spoke with were so eager to talk about how much they loved their friends. You got the sense that they didnt get many opportunities to talk about that.
"I think that we don't give men enough space to be vulnerable with their friends and talk about how much their friends mean to them in the same way."
Six keys to life-long friendship
Accumulation (of time together)
"The more likely we spend time with someone the more likely we are to become friends with them."
Attention
Pay attention to opportunities for new friendships.
Notice when you connect with someone even in an unusual setting and be open to that.
Intention
Be deliberate and intentional about your friendships.
"You need to put in some effort and thought and preparation to help it to grow."
Ritual
The effort of scheduling can be a big barrier to maintaining friendships.
"It helps to have something built into your life that will mean you see your friends regularly.
"If that's baked in I think that takes a lot of the pressure off."
Imagination
"Be willing to think outside of the place that society wants to put friendship in - on the sidelines - and imagine something else for yourself."
Grace
This is grace both in the sense of offering forgiveness and also in a more spiritual sense, and the most important of the six, Beck says.
"We can't always be the perfect friend. Life does get in the way, we have competing responsibilities."
Grace is offering another person the space to be imperfect, she says.
"I really do try to be [a good friend] but I am like anybody else. I have a lot of things going on, I am a slow texter … I often feel guilty for not being a better friend, for not texting back or reaching out more. I think we also have to offer that grace to ourselves and know that if it's a really strong friendship it's not gonna be damaged by the fact you took a few hours to text back."