Most of the time, I'm pretty certain I understand the work of motherhood. It's being a grandparent one day that really worries me.

Two weeks ago, when Little L's arm was injured in a sisterly skirmish, my parents dropped everything and drove 40 minutes to our house to watch MJ -- who was already asleep by the time we diagnosed the problem -- while we scurried off to the emergency room. Six hours later, at 4 a.m., we walked in the door to find them just where we left them: In a brightly lit family room, completely awake, where they had watched a couple of bad movies and two or three rounds of the same cable news programming while waiting for us to return. They never slept. As we were shuffled from one area to the next in the ER, as the hours ticked by and we ruled out any fractures in Little L's injured wing, I had wondered if I had remembered to make the guest bed ... because certainly, my dad, who had to be at work the next morning, would have wanted to go to sleep.

Not only did neither sleep, but our kitchen was sparkling when we got home. The toys were picked up and lovingly put away in our family room. The house looked better than we had left it. We might have had the queen over for tea. But the most startling aspect of the scene was that it didn't surprise me. Not one bit. When I still worked part-time from home, occasionally I would have to go out to an interview for a story. In came Grammy and Pop Pop to watch MJ. And when I came home: Safe, fed and happy baby, down for her nap; watered plants; squeaky clean home. Every time. My dad even sprang our clocks forward or turned them backward, depending on the time of year.

"You don't have to do this stuff, you know," I'd tell them. Because just showing up and watching MJ while I did my job was a miraculous favor in my book.

"I didn't have anything else to do," my mom would say. "I can't just sit around."

Every now and again, when I launch into my woe-is-me-these-kids-are-so-hard-to-raise sob story -- a story that, even as it comes out of my mouth, I realize is ridiculous -- my mother will say, "Well, do you want me to keep one of them one day this week?" (One of them, because even she has her limits these days. She's nobody's fool.) And just about every time she says this, I wonder if I'll be capable of the kind of generosity that they are.

"Oh this is nothing," she says, citing legions of grandparents who spend every day with their grandchildren, practically raising them. I know she's right. I see them in the places I freqent, strolling, loving, scolding, playing. "You'll do the same thing one day. You'll see."

Right now, this is hard for me to imagine. I find it hard to imagine that I'll ever feel compelled to help potty train a child to whom I did not give birth, as my mother valiantly but unsuccessfully tried through what I like to call "Grammy's Lose the Diaper Boot Camp" at her house last fall. I can't imagine suggesting that my grandkid -- the one who's guaranteed to go to sleep too late and wake up too early -- bunk with me during a family vacation instead of with her parents ... just so they could get a little rest.

These are high standards of selflessness to live up to, lofty examples of sacrifice. Grandparenting seems to be more demanding than it's ever been -- maybe even more difficult than parenting -- and I wonder how many grandparents once dreamed of their golden years as a time to reconnect with themselves, only to end up reconnecting instead with a remarkable sense of duty that results in an economy-size box of Huggies in their closet and a high chair permanently strapped to their dining room seating. Randy's parents, 12 hours away in Canada, are similarly involved in the rhthyms of life with their young grandchildren there.

I was not a spoiled child. I am a spoiled adult, however. The world was less convenient when I was small; and yet, somehow, now that I am big, and live in a world of buttons and instantaneousness, I still rely on my parents to help navigate the course of my own parenthood. And to think that they, who are both 66, have another daughter who has two kids for whom they rearrange their lives. They began giving their time in 1968 when my older sister was born and haven't stopped producing by the truckload since. I wouldn't be surprised if my dad has fed and changed more babies in his sixties than he did in his twenties and thirties.

Part of me wonders sometimes if my kids will soon start taking notes on what grandparents do for them, notes that will be translated into marching orders and distributed to us a few decades from now after they've become parents themselves. And in that way, in that karmic way in which actions have a way of returning to you, I probably will help raise my grandchildren one day, forgetting, like labor pain, the constant floor, nose and bum wiping involved. Most of me, however, just wonders what I'd do without my parents, to whom I am endlessly indebted and whose willingness to help is all too easy to take for granted. For today at least, I'm not.

Beth appears every Tuesday on TriangleMom2Mom. Read more about Beth at her blog MotherBunker.