We all have that college friend who drifted away or the former bestie we haven’t seen since her wedding. It’s more common than you’d think; in fact, research shows we replace half our close friends every seven years, according to friendship expert and author Shasta Nelson.

But while replacing friends might be normal, that doesn’t mean it feels good. The effect of losing friendships goes deeper than just feeling guilty or missing their company. Strong social support yields health benefits including better stress management and longer life. And yet, it’s sometimes hard to prioritize making and maintaining friendships: with career and family obligations taking precedence in adult life, friendships can be pushed down the list. We might also be surprised by how much harder it is to make friends as an adult than as a child, when we easily made friends in the schoolyard, at summer camp or at the neighborhood pool. 

“Friendships felt automatic when we were kids, but it was the consistency that was automatic,” says Nelson, also CEO of GirlFriendCircles.com, an online community for making and maintaining friendships. “We both just showed up to school every day.” Consistency is one of the main reasons we tend to make friends at work, but Nelson says we can create consistency with potential new friends by signing up for a class, a parents’ group or other recurring activity. In addition to consistency, vulnerability and positivity are the other two components of a healthy, meaningful friendship, according to Nelson. When one area changes, it also impacts the others.

Here’s a look at several life changes that can strain friendships and how to navigate them.

Moving away

Moving away can strain a friendship because it disrupts the friendship’s consistency, whether you were gym buddies or drinking buddies. If you’re moving away, you’ll need to balance the desire to stay in touch with old friends with the need to make new ones nearby. “Most of us can’t stay in touch with everyone we knew at a meaningful level, so are there one or two people that it really matters to me to stay in touch with in a meaningful way?” Nelson asks. 

Discuss how you’ll stay in touch (perhaps weekly Skype sessions, phone dates, or even emailing once a week to kvetch) and schedule it, because if too much time elapses between contact, you’ll be less likely to reinitiate contact.

Changing jobs

When you leave a job or your work friend leaves, it’s likely to impact that friendship because you won’t see each other in that same context anymore. Nelson says this often causes hurt feelings, but it’s just a reality of the situation. “Offer suggestions to the friend and ask the friend to help brainstorm how you can best stay in touch outside of work,” Nelson says.

If a coworker leaves under less than ideal circumstances, she may want a clean break rather than rehashing office gossip over margaritas, so be prepared to discuss other topics. If she still doesn’t want to remain friends, don’t take it personally. But ideally, this becomes a jumping ground for helping each other with your careers. It’s much easier to act as mutual mentors and share connections when your colleague goes to work somewhere else.

Getting married or having a kid

When a friend enters a new life stage such as marriage or kids, or even just a new relationship, it can change the consistency of your interactions and also the nature of your friendship, especially if you’re not dealing with those same things. “Our life is changing so therefore it makes sense that our friendships need to shift and change as well,” Nelson says. “We come up with a new normal or end up drifting apart.”

If your normal had been hitting the bars every Friday with your friend, but they’ve found themselves in a committed relationship and less interested in going out, try shifting that normal to wine on their patio on Thursdays. Or if your favorite running pal can’t leave the house because of a new baby, suggest a workout you can do in her living room. Lift that baby!

If you want to maintain the friendship, Nelson suggests letting the friendship evolve and being prepared to talk about the changes in your friend’s life. “We don’t want to shut down our friends from talking about what’s most important right now,” Nelson says. “One of the most important things we can do is to give permission for people to share.”

Lifestyle changes

Sometimes it doesn’t take a new girlfriend, new husband, or new life for someone’s lifestyle to change. Many times, as people grow and develop, their habits change, too. If your bonding point was always over drinks or barbecues, and your friend decides to stop drinking or change their diet, it can really disrupt the flow of the friendship. But if your foundation is solid, it should survive the transition. Remember, it can be really difficult for your friend to feel comfortable in the same environments as before when making these changes. Instead of suggesting your friend join you at the bar but not drink, why not ask him to lunch instead? And if a friend has changed their diet, research restaurants that support those changes in advance. It’ll go a long way in making that person feel secure in the friendship.

Dealing with a crisis

When we experience a divorce, the loss of a loved one or another crisis, some of us turn to friends for support and others turn inward. A crisis can also sour friendships if it turns us into a Debbie Downer and drains the positivity from the relationship. Of course you want to confide in your close friends—and you should; vulnerability is a key part of meaningful friendships. However, “even when we’re going through crisis, you need to be mindful of still contributing positivity to the relationship,” Nelson says. “Be grateful [for her support] and give her permission to still be happy [even if you’re going through a rough time].” 

If your friend is going through a crisis, let her know you’re there for her but don’t force it. Maybe she doesn’t feel like talking and prefers to binge-watch rom-coms with you. Perhaps she won’t want another sympathy lasagna but would love someone to watch the kids while she enjoys much-needed me-time. Offer specific ways you can help, but ultimately let her choose what she needs. Even if you don’t know what to say to a grieving friend, being physically present can mean a lot.

Friendships evolve and not all of them last forever. But nurturing the important ones is good for your own mental health and that of your friends.