One of my favorite poems by Rainer Marie Rilke begins “I live my life in widening circles”—and I think this active openness to friendships is something we should all work to develop.

Friendship is one of the more challenging parts of adult life. Growing up, my mother used to tell me that as an adult I’ll be lucky to have five or six true friends. As a child for whom every kid at the park was a potential bestie, I couldn’t comprehend this advice. But as I approach the big 3-0, I’m realizing the truth of her words.

Friendships require energy to develop and maintain. I never experienced this growing up and only discovered this harsh reality in my first post-college years when my closest friends no longer lived right down the hall. Close friends moved away, and local friends were as invested in their work and families as I was; exhaustion from work and family obligations often leave our tanks close to empty. So, for the first time, I struggled to find time to maintain and deepen the friendships that had started so organically.

Over time, I’ve come to feel this lack of physical closeness as a real inhibition to friendship. Of course we have social media and FaceTime (and their old-fashioned counterparts, writing and calling) to keep in touch, and true friendships do last despite the lack of shared experiences, but they take serious work. And I think that even with all these tools and tricks, there’s a kind of intimacy which is bound up with living life side-by-side. Physical distance creates emotional distance, and I find myself looking more and more to local friendships for the day-to-day support and rejuvenation we need from relationships.

But, as the good book says, true friendship is hard to come by. Opportunities for friendship do abound, at least in a generic sense: between work, church, neighborhood, community groups, rec leagues, book clubs, and the like, potential friends are everywhere. But even if you can overcome the paralysis of so much potential, there’s an additional struggle. Acquaintances are wonderful to have—they make neighborhood living a source of real joy—but they’re not enough. We all want deep and lasting friendship, but how can you tell which newly-budding friendship will last? How do you know how to invest your time? In a way, it’s terrible to think about relationships in monetary terms, but the truth is we all do have limited time and emotional resources available to us, as well as distinct things we need from and bring to friendships.

Of course, these questions can’t be answered with certainty. Time, as they say, will tell. But if you think about friendship the way you think about dating, you’re more likely to invest well from the beginning. Look for friendships in places where you’re guaranteed certain shared points of worldview. Whether that be through joining a volunteer group, attending a lecture on a topic dear to your heart, befriending your neighborhood cycling coach, or singing in the church choir, look for places where you’ll meet people with whom you share similar values from the get-go.

But another way to make new friends—and the most successful, in my experience—is a friend “setup.” We trust our friends’ judgments when it comes to men (at least enough to give the guy a chance!), so try doing the same with friends. Merge your friend groups—or allow yourself to be merged!

I’m writing this having just returned from a study weekend that my good friend and colleague (let’s call her Jackie) organizes every semester. I generally don’t know the other women on the trip (and if I do, only slightly); our middle term is friendship with Jackie. I’ve always admired Jackie’s willingness to gather together people from the many different areas of her life, and the result is always lifegiving. Whether at a party or study weekend or a barre workout with group drinks afterward, the collection of distinct but compatible personality types and interests makes for a wonderful time.

This particular weekend involved a law student, a philosophy Ph.D., an art history Ph.D., and two literature buffs. Our conversations ranged from food to fashion (Everlane is our collective favorite brand!), from what it means to be a woman, to how you manage your in-laws. These conversations are all ones I’ve had before—we all have—but the combination of friends and half-friends and strangers-who-are-now-friends made these conversations particularly fruitful.

It’s sort of like cooking: if the individual ingredients are good quality, the combination should work out pretty darn well no matter what. In this way, friend-merging is a kind of an act of trust: when you bring together different groups of friends, you are the common denominator for all these people, all of whom you love for good reason. And I’ve found that different qualities of myself and of my friends rise to the surface as we change the contexts of our friendships. You may learn things about your closest friends that you didn’t know before, see sides of their personalities that weren’t brought out by your one-on-one interactions—even come to recognize qualities of yourself, your personality, and your worldview that weren’t as clear to you before. So trust that, when you put them together, things will go well. At worst, the groups don’t merge; c’est la vie. At best, you’ve deepened your own friendships and self-knowledge and you’ve gifted a few new friendships.

Now, I’m not saying that you should merge your groups entirely or all the time. This likely isn’t possible, anyway. It can be important to have different “spaces” in which different parts of yourself are active and are activated. It’s also important to have individual friendships in addition to group ones. But the occasional deliberate cross-pollination can deepen pre-existing friendships and introduce you to new ones which have the potential to become the staples of your local life.

So whether you’re the one doing the merging or one of the ones being merged, take advantage of your friendships to build more, truer, and deeper relationships.