My mother is 92. She has lived long enough to see her children become grandparents, neighborhoods change, and the world reinvent itself more than once. She has also lived long enough to say goodbye to people she expected would always be there.

My father died at 86. Last year, my mother’s best friend in the neighborhood died at 89. Now another dear friend, just 77, has been diagnosed with inoperable cancer.

When I think about what it means to live a long life, I often think of the extra birthdays, the family celebrations, and the chance to watch another generation grow up. I think less often about this part: the accumulating goodbyes.

A spouse’s death changes the shape of a life. But the loss of a friend can change it, too. A friend may be the person who calls just to talk, who brings you your mail each day, who knows the neighbors, who remembers the story behind a familiar photograph. When that person is gone, it is not only the big occasions that feel different. It is an ordinary Tuesday when there is something to tell him or her, and you remember you cannot.

Longtime friends offer something even family cannot always provide. They knew us before we became the people our children know. They remember our old homes, our younger selves, the jokes that need no explanation. As the years pass, there may be fewer people who can say, “I remember that, too.”

Research on bereavement in very old age has found that the loved ones who die are often siblings or close friends. That makes sense, yet friendship grief does not always receive the attention it deserves. When someone loses a spouse, people generally understand that life has changed. When someone loses a friend, we may offer condolences without realizing how much that person’s daily life has changed, too.

I wonder what goes through my mother’s mind when she hears that another friend is seriously ill. Does she think about the memories they share? Does she worry about what her friend is facing? Does each loss make her think about her own mortality? I don’t want to presume to know. Those are questions worth asking her and then listening to the answers.

What I do know is that my mother’s life is still full of people who love her. Her sister, brother-in-law, and childhood friend are all 91 and thriving. She has three daughters and their extended families. We talk every day, and I cherish that we can.

None of those relationships erase the loss of my father or her friends. Nor should they have to. We can be grateful for the people beside us and grieve those who are missing from the room. Perhaps part of growing older is learning to carry both feelings at once.

For those of us who love an older person, there is a simple lesson here: ask about their friends. Remember their names. If a friend dies, check in again after the funeral, when everyone else has returned to their routines. Invite the stories, even the ones you have heard before. “What was she like when you first met?” can open a door that “How are you doing?” may not.

And if you are the one who has lost a friend, you do not have to measure that grief against anyone else’s. The years you shared mattered. The small rituals mattered. The empty space they leave matters.

A long life is a gift, but it asks something of us. It asks us to keep loving people while knowing we cannot keep them forever. My mother’s friendships remind me that this is part of the courage of old age: to mourn the people who are gone, treasure the ones who are here, and still make room for connection tomorrow.