Friendships are living breathing things—just like the people who are in them. That’s to say, they can change over time, growing stronger or weaker due to any number of factors, from personal life events (like moving to a new place, changing jobs, or getting married) to broader shifts in how we tend to interact (as a result of the growing influence of technology on relationships) and even just the simple passage of time. But even as relationship dynamics ebb and flow, there are a few core elements of any good friendship, whether close or distant, that tend to hold constant.

Broadly speaking, most of the key qualities of good friendship hinge on a simple tenant of any relationship: being present. Or, as friendship researcher and coach Madison Romney puts it, being “psychologically available” to the other person.

“Although our attention is easily consumed or deflected these days, when we deliberately direct it away from distractions and toward our friends, it activates a sense of strong, mutual connection.” —Madison Romney, friendship researcher

“Although our attention is easily consumed or deflected these days, when we deliberately direct it away from distractions and toward our friends, it activates a sense of strong, mutual connection,” says Romney. That presence of mind is something a friend will feel and appreciate, no matter the circumstance or even the rung or level at which this friend exists in your life—whether they’re a “best” or essential friend, a fringe friend, or anything in between.

These differences in intimacy among your friends, however, do affect just how strong a role each of the below elements of friendship will play in the relationship, says counseling psychologist and friendship expert Marisa G. Franco, PhD. As you might imagine, the closer the friendship, the more essential each of these factors will be in ensuring it continues to thrive.

Below, the experts share the elements that make up a healthy friendship and why they’re so necessary for keeping that bond intact over time.

The 7 core elements of friendship, according to friendship experts

1. Reciprocity

Any party to a friendship has to both give and take, says Dr. Franco: Too much giving, and you’ll start to resent the other person; too much taking, and you’re not upholding your half of the friend bargain. “Essentially, you both need to consent to the relationship because of the responsibility it entails,” she says.

That also means agreeing on just how much giving and taking you’ll each be doing. “A friendship will work best if you consider each other as the same caliber of friend,” says Dr. Franco, referencing a scale created by friendship researcher and author Shasta Nelson. “For example, if you rate a friend as a 10 and they rate you as a five on a scale of one to 10, then you have a misalignment of expectations where you’re expecting a 10-level of investment in the relationship—which might look like inviting you to everything or showing up when you’re sick—but they’re only expecting half that amount of effort,” she says. Getting on the same page about where you fall in someone’s broader friendship scheme (and where they fall in yours) can help you avoid either letting a friend down or being let down.

2. Support

Difficult scenarios tend to separate our closest friends from our less-close ones for a reason: Depth of intimacy requires a friend having your back, not only when doing so is easy, but also when it’s painful or tough. “Celebrating a friend after they have a baby is just as vital as consoling them through a job loss,” says Romney. Though this dimension of support will vary across the friendship spectrum (that is, not every friend is going to be the one that visits you at the hospital), the idea is that the level of support—like the energy you pour into a relationship, generally—is matched and reciprocated.

This is tied to the idea of mutuality in a friendship, too, adds Dr. Franco. “That means you’re able to consider not just your needs, but your friend’s needs, as well, in all scenarios,” she says. For example, if your friend were to bail on your birthday party because they had to go to the hospital, you’d be able to understand, ‘Okay, I have my need for them to come to my birthday, and they have their need to go to the hospital,’ and from there, you’d be able to weigh both needs in perspective. In doing so, you’d come to the conclusion that, in this case, their need outweighs yours—but, of course, in another situation, it might be the reverse.

3. Boundaries

Setting boundaries might sound like erecting a wall between you and a friend rather than allowing for the flow of intimacy. But in practice, boundaries can actually help outline how you’ll navigate your relationship in a way that takes both people’s needs, desires, and expectations into account, says Romney. “Setting a boundary with a friend can be as simple as being clear about what days of the week you can or can’t hang out, what activities make you uncomfortable, or what you need from them to feel supported and loved,” she says.

For more expert advice about the importance of boundaries and how to set them, listen to the Well+Good Podcast episode on this topic below.

4. Affection

It might sound obvious, but you actually have to like a friend better than you would a stranger in order for the friendship to work. “You don’t necessarily have to love them, but you do need to hold them in positive regard and act in a way that shows your affection,” says Dr. Franco. (By contrast, one of the most common traits in toxic relationships is one or both people tearing the other down.)

“A healthy friendship is one that fills you up with energy and positivity more often than draining your emotional resources,” says Romney. Often, someone might stay in a negative or draining friendship merely because they’ve been in it for a long time or because they don’t think they have handy alternatives, says Dr. Franco. “But when they actually evaluate, ‘Do I like this person?,’ they might realize that they don’t—and that alone can cause the friendship to suffer.”

When you do like a friend, a spiral of positivity unfolds: “Showing a friend that you like them makes them more likely to feel secure in the relationship, and, in turn, to act in pro-relational ways, which can then deepen and strengthen the relationship,” says Dr. Franco.

5. Ease

A friendship can flourish only when both people in it feel comfortable around each other. “If you always feel like you need to be on guard or like you’re walking on eggshells, you won’t reap the social-health benefits of true friendship,” says Dr. Franco.

In that vein, a good friendship also has to be void of any power dynamic, she adds: “If one person holds more power than the other, the second person can never really be at ease, or have the latitude to be their authentic self and get their needs met.”

6. Vulnerability

“When we share privileged information, disclose personal feelings, and accept support, we build intimacy in our friendships,” says Romney. While this element of friendship will be that much more potent with a close friend, feeling able to share some degree of personal information with any friend is necessary for a below-surface-level connection. An ability to be vulnerable is also both an indicator that you have a foundation of trust in place (which is necessary for basically any relationship) and a way to foster even more trust, too.

7. Predictability

While any friendship can ebb and flow over time, some consistent sense of forward momentum is necessary to keep it intact. In other words, there need to be clear expectations for the level of communication and connection you’ll have with a friend, whether that means texting every day, calling every week, or getting together for a longer catch-up once a month, says Romney.

When that coalesces into a rhythm, it breeds (even more) trust: Each person can rest assured that when they reach out, they can expect a response in return. And the more this pattern repeats itself, the more readily they’ll be able to predict what that response may be, says Dr. Franco, which just makes both people that much more comfortable getting vulnerable—a positive friendship cycle that reinforces itself.

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