Early on weekday mornings, my mother-in-law boarded one bus in Williamsburg, Brooklyn, then switched to another for the 90-minute trip to our apartment in Forest Hills, Queens. Now just past 65, Antoinette Chirichella suffered from severe osteoarthritis that forced her to walk with a waddle.

She had only recently retired from her job as a seamstress in a factory. She had hunched over a sewing machine for 47 years — a career started when she dropped out of eighth grade at age 14 to help support her family of six — and raised her only child by herself. Now she was reporting for duty in the highest of callings: to take care of her two grandchildren for the day.

Our kids knew her as grandma, while everyone else called her Nettie. 

She would arrive at the front door to our apartment, thereby instantly freeing my wife, Elvira, and me to go to our full-time jobs. Handsome and olive-skinned, with warm brown eyes and a saintly smile, Grandma Nettie then devoted herself to looking after Michael and Caroline, ages seven and two, until we came home.

Now let’s fast-forward 30 years. Here comes grandma again, only now it’s Elvira, now past 70, who’s swinging into action. 

She’s gone to Caroline’s house, a 10-minute walk from ours here in small-town Southern Italy. There, Elvira will likewise step into the breach and mind our grandchildren, Lucia and Nicola, now also ages seven and two. Caroline will be liberated from childcare for the day to operate her business as her husband Vito runs household errands around the neighborhood.

A tradition is thus honored, an inheritance endowed, a torch passed. Lessons that are learned about the job of grandmother are handed down from one generation to the next, creating a continuum of commitment that connects our families across the decades.  

None of this is new, of course, but it’s no less important for being old. The central role of grandmothers in societies ancient and modern, particularly as teachers who set an example in bringing up kids, is impossible to overstate.  

Some studies show, for example, that mothers may inspire daughters, based on lifelong observation, to mimic how they themselves raised kids. Ideally the daughters follow the same formula of  guidance and discipline balanced with unstinting attention and unconditional love. Experts call this process “intergenerational modeling.”

With such grandmas around to help serve the cause, children can grow up feeling safe, secure and, yes, at least ever-so-slightly spoiled. Some research suggests that what mothers teach daughters about raising children may enable those third-generation kids to develop better cognitively, socially and emotionally.

Grandmas are still doing what grandmas have always done. They’ve pitched in on taking the reins to bring up children for millennia. Like Nettie and Elvira, they’re rarely hampered by nuisances such as osteoarthritis or nearly a half century toiling to stitch together garments in a factory.

But lately the grandma has grown even more important than ever. With more mothers working jobs since about 1970, they increasingly need — and depend heavily on — grandmas to come to the rescue and lend a hand with the kids.

When it came to being a grandma, Nettie set the standard for Elvira. My beloved mother-in-law took our kids for walks everywhere—parks, stores, restaurants, playgrounds — despite her difficulty hobbling around. She cooked fried cauliflower and showed the kids off to our neighbors, soothed Caroline as she cried and Michael as he suffered ear infections. She adored those kids, but no more than they adored her. “They’re my everything,” she once told me.

Now Elvira, equally close with Caroline, follows the same maternal principles, the same business model, the same best practices as homemaker and caregiver. Call it a peaceful transfer of power.

Elvira is on call 24/7, fully vested in the enterprise at hand, by turns hard and soft in running the show. One minute she’s doting and generous and encouraging, the next she’s cracking down to tell the ever-rambunctious Lucia to settle down and urging the always insatiably hungry Nicola to stop opening the refrigerator to fetch himself a snack until she can feed him herself. Oh, and how she cooks for those kids, whether the fluffiest pancakes or French toast.

How fitting, too, for this scenario to play out in Italy of all places. Here, as much as or more than any other place on the planet, the grandmother is revered as a matriarch, the capo di tutti capi or boss of all bosses.

Plus, in an eerie echo of history, Elvira also has severe osteoarthritis. She even walks much as her mother walked, rocking from side to side, as if channeling her spirit. But she never lets her limited mobility even remotely threaten to stop her from doing her duty with Lucia and Nicola.

My own maternal grandmother was much the same with me. She pulled out all the stops to make sure I grew up right. That’s just what all the best grandmas do. And as Elvira now proves daily, every inch her mother’s daughter, nobody will ever do it better.

Bob Brody, a consultant and essayist, is the author of “Playing Catch with Strangers: A Family Guy (Reluctantly) Comes of Age.”