When you get to my age (68), you arrive at crossroads that are different from the ones you encountered before.

The choices may be similar. But the decisions you make have more importance because you don’t have decades ahead of you to start again if you end up on the wrong trail. Even a decision as insignificant as buying another car is a bit more challenging because you recognize (at least in some corner of your mind) that this may be the last vehicle you will ever drive.

A more important decision – because it affects so many parts of your life – is how much socializing you are going to do.

In my high school and college years, I had all sorts of social relationships. My immediate family, the kids in my neighborhood, my fellow football players, and so on. When K and I had kids, the number of social groups I was involved in changed and diminished. Now it was some neighbors, some workmates, and the parents of my children’s friends.

The way this usually goes is that your circle of friends narrows again after the kids go off to college. And then it narrows again as old friends start to die. To make matters worse, we tend to drop friends as we age. They do something we object to and we find it’s not as easy to forgive them. It’s easier to just stop seeing them. After all, there’s plenty of stuff to watch on TV.

Having friendships, it turns out, is about much more than just social amusement. According to studies that keep popping up, staying social as you age keeps you healthier in mind and in body and is the single most important factor in terms of longevity.

I am rich in friendships. Not because I’m a gregarious person. I’m not. But I do have an irrepressible curiosity about people, and especially about people that are new to me. So I’ve always been a “joiner” and a starter of groups. These days, for example…

The Mules Book Club: 12 to 14 very interesting and accomplished men that meet once a week to have philosophical discussions based on our diverse reactions to reading books ranging from a biography of Thurgood Marshall to Lolita by Vladimir Nabokov.

My Jiu-Jitsu buddies: A larger group of about 30 athletes, mostly but not exclusively men, mostly younger than me, whose interests range from sex to politics to yoga to surfing to the life lessons Jiu-Jitsu can teach us.

The Cigar Bar: Every Friday, my private Cigar Bar is open to family, friends, and colleagues to stop by for a drink and a smoke or just to talk about their week. Despite the cigar smoke, this group is about 35% women, and that percentage is increasing. (A good thing!)

The Salon: Once a month, I invite a dozen people whose intelligence I admire to discuss everything from estate planning to anthropology to philanthropy, etc.

The Movie Club: Another monthly event, this one hosted by a friend and film expert. We eat buttered popcorn, watch an artsy classic (e.g., Jules & Jim, 8 ½, Blow-Up, The French Connection), and talk.

Joe’s Estate Planning Group: Organized by a friend and former colleague of mine, this is a group of super-wealthy professionals and entrepreneurs that are old enough to be thinking seriously about what they should be doing with their money. At every meeting, we have an expert speaker. And after each speech, we have a conversation. Two recent topics: “A Proven Stock Strategy for Long-Term Growth” and “When and How to Get Your Kids Involved in Your Estate Planning.”

Since I’ve been thinking about estate planning for nearly 20 years now, little of the information is new to me. But I do enjoy getting to know some of these rich old geezers and hearing their stories about how they made their fortunes.

My writing friends: I know lots of published authors. Most don’t like to talk about their craft. This is an informal email group of about a half-dozen that do. Most of the time we bitch about how hard we work. I like these conversations immensely.

My art world acquaintances: As an art collector for so many years, I’ve developed a good-sized Rolodex of artists and brokers and other collectors. But until Suzanne Snider took over as director of Ford Fine Art, I never socialized with any of them. Nowadays, several times a year, I get to travel to interesting parts of the world and have face-to-face conversations with all these interesting people.

My Spanish- and French-speaking friends: I wouldn’t have thought of this as a separate social group, but in fact, I’m in regular contact with about a half-dozen people with whom I speak only Spanish and another 3 that I speak to in French. When you speak a second language imperfectly, as I do, you don’t have the ability to convey the depth of your personality as you do in English. You have to settle for being someone who is slower in thought and less clever in speech. This is a wonderfully humbling experience.

Old friends: I’m lucky to be in regular contact with about a dozen friends from my high school days. And the number is growing thanks to a recent 50th year reunion. I am also in touch with a half-dozen friends from my days as a Peace Corps volunteer in Africa. These friendships are sustained mostly through email. But when we do get together once or twice a year, the closeness is almost astonishing.

Business partners, competitors, and colleagues: When I got into the publishing industry in 1977 (after Africa), I worked for a small business and was on friendly terms with everyone else who worked there. Nowadays, I have interests in dozens of businesses with thousands of employees, so I can’t possibly know even the names of 10% of them. But I am still fairly close to several dozen colleagues that I’ve worked with over the years. These are not regular relationships, but they are based on so many years of shared experience that I consider them valuable.

My family: It seems that most families I know are broken. In one case, nobody speaks to the father. In another, the mother ran away with the butcher. I know dozens of people that don’t speak to a sibling or a parent or even a child for some reason. And then there are so many families – like the one I grew up in – where cousins have never even met one another.

I didn’t want this to happen to our families. So about 30 years ago, we began sponsoring what we call cousin camps – child-focused family reunions. This had the effect of bringing all of us closer together.

My readers: And finally, there is the much larger but less proximate community of my readers. The hundreds of thousands of people whose names I do not know, but who have nonetheless honored me by reading my books and essays. At least once a week, I get a letter from a reader that makes me feel I’m not wasting my time by continuing to write.

Now that’s a lot of social connections.

But what a blessing! I seldom suffer from loneliness or ennui. Every day, I have not only good work and challenging projects to look forward to but also smart and interesting and sometimes crazy people to do it with.

And I never forget that this is all a result of a dozen conscious decisions I took at some point in the past. When given a choice to say yes to being with others or being by myself, I chose others, even when it would have been much easier to choose myself.