By Holley Gerth

Make new friends but keep the old, one is silver and the other gold.

It turns out there might be more truth to that simple saying than we think. Friendships have a vast number of benefits-from improving our happiness to lengthening our lives. But while we’re coached from the start of our career on how to bolster our 401k retirement accounts, we get a lot less training on how to do the same with our relationships. Fortunately, many of the same concepts apply. So here’s a little guide for building your very own friendship 401k.

Invest
The first thing we have to do with a 401k is put something in it. The same is true of friendships. While retirement accounts require money, friendships need something even more scarce-time.

Yes, it’s going to cost us. But in the end we may reap benefits we didn’t expect. For example, Dr. Joan Borysenko told Prevention how she instructed an attendee at one of her seminars suffering from frequent headaches to spend two nights a week with friends. To her client’s surprise, the headaches cleared up and she could be even more productive.

Diversify
We know not to put all our eggs in one basket when it comes to picking investments. But the same is true when it comes to picking friends. Thinking that one friend can meet all of our needs isn’t fair to us or to her.

In a 401k, we’re told to have variety in our portfolio. We need some high risk stocks with great potential for growth. That might be the new friend we’re just getting to know. She might turn out to be one of the greatest friends we’ve ever had. A high risk friend might also be someone who is different than us. Having friends who stretch and challenge us is important for growth.

We also need some low risk stocks that will steadily build what we invest. These can be old friends who are tried and true. We know they’re going to be there for us. But we can even diversify with them too. One friend might be our shopping buddy, another our “deep talks” over coffee confidante, and a third our exercising partner.

Roll Over
When we switch jobs, it’s tempting to cash in our 401k. But there are financial penalties for doing so. That’s why most experts recommend doing a roll over to a new tax free account.

We can also be tempted to cash in our friendship 401ks. We may move and keeping in touch feels like too much work. Or perhaps we lose track of a former coworker when we make a career switch. At the time, it may not seem like a big deal. But doing so over a lifetime can cause us to lose out on big benefits. Money left in a 401k grows exponentially over the years. So when we cash in, we’re not only losing money today, we’re also missing out on future gains.

Ideally, friendships work the same way. Over the years the relationships we build snowball into an ever-growing network of support. This support is especially important in later years. In an article for More, Laura Fraser reported that in a study of people 70 or older, those who had the most close friends (four or five) were 22 percent less likely to die over the next 10 years. Keeping relationships intact can actually lead to a longer, healthier life.

Patricia Gottlieb Shapiro, author of Heart to Heart: Deepening Women’s Friendships at Midlife, told Health, “Your friendships with other women are going to be longer and truer than just about any other relationship-so hold on to them. These are the people who will sustain you over the years.”