Remember “The Talk,” when mom or dad sat you down to explain the facts of life?

Well, it may be time for you to initiate “The Talk” again, but focusing this time not on how life begins but how it should end, even if that end is not for several decades yet.

“I hope people will recognize there are things they should think about today to plan for their future,” said Nancy Orel, director of the gerontology program at Bowling Green State University in Ohio. “I rarely hear people say, ’I can’t wait until I’m old.’ I hear people say, ’I can’t wait until I retire,’ but that’s an ending, and they have to reinvent themselves.”

While important for everyone, planning for all the what-ifs of senior life is especially crucial if you are living alone. And let’s face it, even if you have a partner and/or kids, there’s no guarantee any of them will still be around when you need them. Do you know who is going to be there to step in with comfort, guidance and rational medical advice when you are old? Start answering those questions now, no matter your age, gerontology experts say.

“(People) need to start planning, and they need to look forward to it,” Orel said. “I hope someday to hear someone say, ’I can’t wait to get old,’ with the same enthusiasm as someone wanting to turn 21.”

Graying baby boomers offer a cautionary tale for those inclined to wait, only to realize they may have waited too long. A recent study by the university’s National Center for Family and Marriage Research found one-third of adults age 45 to 63 are unmarried, a more than 50 percent increase since 1980.

Susan Brown, the center’s co-director, said these unmarried boomers tend to be more vulnerable economically, socially and physically than their married counterparts.

“Usually when people are married, spouses are the first line of defense,” she explained.

More people are single for a variety of reasons, Brown said. Some may have delayed getting married and eventually let go of the idea, she noted. Others are single because of divorce, an experience that she said can be especially difficult economically for women. What’s more, those marrying later may choose (or be forced to choose) not to have children.

“The pathways we take as young adults have ripple effects through life,” Brown said. “This is a lesson for younger people. You want to enter old age with as many resources as you can.”

Orel conducts much of her research in the lesbian, gay, bisexual and transgender community. The “resilience and strength” she has witnessed offer examples for others to learn from.

“That population provides a lot of connections,” she said. “People become connected through LGBT groups. They voice concerns. They build strong families of choice. They participate in the community so they don’t have a sense of being alone.”

Eric Klinenberg is author of “Going Solo: The Extraordinary Rise and Surprising Appeal of Living Alone” (Penguin Press). In it, the New York University sociology professor notes more than 50 percent of American adults live alone and are learning new and often richer ways of living by going solo. Still, he said, it is difficult to grow old alone.

“An enormous number of people have to be bracing for the possibility that they will,” Klinenberg said. “The good news is they’ll have plenty of company. The bad news is we, as a society, have done little to promote the health and security of aging single seniors.

“When I did interviews for my book, I met with a lot of older people living alone who spent a considerable amount of time developing support systems of friends and neighbors as well as family in case of an emergency.”

In the new movie “Robot & Frank,” actor Frank Langella plays a retired cat burglar whose children think he can’t live alone anymore. Instead of sending dad to a nursing home, the kids get him a robot programmed to improve his physical and mental health, and much adventure follows. But that film is fiction and set in the near future - maybe you’ll be lucky to live long enough to see robotic caregivers become a reality.

Right now, though, there’s no Hollywood ending to the challenge of growing old alone. Like so much else in life, planning depends on each individual situation. But the key is to take responsibility, experts say, and begin doing that thinking and talking now, even if that triggers plenty of seat-squirming.

“We all hope we’ll get old, but we don’t plan to get old,” Orel said. “You have to have the conversation before there’s a crisis.”