People talk about the first glimpses of their first grandchildren in terms borrowed from romantic poetry: They swoon. They find every finger and eyelash beautiful, perfect. They melt into helpless puddles of love.

What I felt when I first met my granddaughter, hours old and sleeping off the rigors of birth, was a bit different: familiarity. Cradling her, instinctively supporting her wobbly neck, I thought, Oh, right. I remember this.

I recalled the way newborns smell. I changed her as automatically as if 10 minutes had passed since I last dealt with diapers, when it had actually been 30-plus years.

When she started to fuss a bit, I shifted without thinking into that jiggly rocking motion that somehow comforts infants, and she quieted.

“Nice job, Bubbe,” said my exhausted daughter from her hospital bed, using the name I had claimed (it’s Yiddish for “grandmother”) the minute she’d told me of her pregnancy.

But as the baby I call Bartola (as an affectionate nod to the former Mets pitcher Bartolo Colon) approaches her first birthday, I’m seeing that not everything I remember fits with contemporary parenting practices.

Some customs endure; some skills are timeless. But over the decades, other things change — a lot. You have to keep up.

Take something as elemental as sleeping. Every Thursday, when I serve as Bartola’s day care provider, I’m reminded of how I used to place her mother in her crib when she was a baby.

Her father or I settled her on her belly, which supposedly prevented choking if she spit up. We had tied cheerful gingham bumpers around the crib’s perimeter, so she wouldn’t bump her head on the slats. We tucked blankets around her on chilly nights, and we tossed in a stuffed animal or three for company. It was all very cozy.

We’d vaguely heard about what was then called “crib death,” and is now known as sudden infant death syndrome, but regarded it as a distant tragedy; it might be randomly, mysteriously visited upon you, but we didn’t know it was something you could help prevent.

By the time public health agencies started information campaigns that sharply reduced SIDS, we had a schoolgirl and didn’t need such precautions. But every part of our routine was wrong, and if I used it for Bartola, her parents would react with justifiable horror.

So, as pediatricians recommend, I put the baby on her back, the safest position, in a spartan crib that holds nothing soft or yielding.

This is becoming moot: Her mother heard strange noises at nap time recently and walked in to find the baby standing in the crib, happily attacking the mobile. Still, lesson learned.

On the other hand, today’s new parents have fewer fears about other things.

Germs, for instance. We used to wage war on microbes. For the first three months of our infant’s life, we scrupulously boiled bottles, nipples, pacifiers — anything that might come in contact with her mouth; after that, we sterilized things in the dishwasher.

None of that for Bartola. Her bottles, when she started using them, just got plunked into a bowl of soapy hot water. It appears that our attempts to create pristine environments for children just encouraged allergies and asthma, so our grandchildren are freer to get dirty and develop healthier — to use a phrase unknown to me in days of yore — microbiomes.

I saw this generational divide recently when my daughter and son-in-law traveled out to my New Jersey town for a museum event. They were bringing Bartola, so I invited a few local friends to come meet her.

“Are they bringing a portable playpen?” one asked.

Nah, I said, she’ll just crawl around on the floor.

“The floor? The filthy floor?” You’d have thought we were going to plop her down on a subway platform. But that was my parenting generation, when germs were scary but blankets weren’t.

In fact, the first few times I took Bartola to the playground in Brooklyn, she enjoyed the baby swing so much she started licking it. Her mother, duly informed, was untroubled. “It’s good for her immune system,” she said.

Technology has brought a bunch of change too, of course. How did I remember which side I had nursed on, or how long ago? I suppose I scrawled it on paper. My daughter, Emma, took notes on her phone. (She also, while pregnant, used an app that each week announced, among other information, what fruit or vegetable the developing fetus resembled in size, from mango to turnip to butternut squash.)

We had a monitor so that we could hear the baby from another part of the house. Bartola’s parents have a video monitor.

I thought this unnecessary, when Emma told me about it. But a large part of Effective Grandparenting 101 is, if your children tell you it’s reassuring to actually see a newborn’s chest rise and fall while she’s asleep, you nod and shut up. In fact, nodding and shutting up should probably be your default response to just about everything.

On balance, though, Bubbe-ing seems more familiar than not.

Much of what grandparents know still works, from silly songs about wheels on buses to the physics of propelling more mushy food into the baby than onto her.

Besides, we’re calmer now, more aware that babies get raised in all sorts of ways and most come through it fine — a useful insight. We’re still vigilant, but also committed to letting kids explore their environments, and we hope we get the balance right.

In fact, we hope we get most things right. But since a long time must pass before we learn whether we did (and to be honest, some of us will not be around for the denouement), we take a big leap of faith and hope that love and common sense will prevail.