I have a small plastic tub tucked under the stairs in our new Denver bungalow, where a normal Coloradan might keep skis or camping gear. In New York, it lived on a shelf in the girls' already tiny closet.

What is precious enough to take up such prime real estate, you might wonder? The treasure of motherhood: the tactile, tangible evidence of bearing a human being and raising her through all her early stages of life. Memories.

How could a mother part with the hospital newborn cap—the one that, if you squeeze your eyes shut and sniff really deeply, still smells a little like fresh baby? I couldn't give up on the dress I sewed that only fit for a few weeks by the time I completed it in the face of rapid infant growth. And oh, the handmade mobile that was gifted to us by a thoughtful friend, with brightly colored birds and a small branch plucked from an Indiana maple tree.

It was easy to justify saving everything after my first daughter was born, especially when I wound up pregnant again so quickly — especially when I found out it was another girl. When the first outgrew something, into the tub it went, ready to be used again. Practical. It was pragmatism that grew the one plastic tub to four or five plastic tubs. But we haven't needed baby clothes for a while now. Our babies are now three and five; and after four moves, I've had to face the dreaded task of paring down.

There are all sorts of books and tools on decluttering. I can absolutely get on board with the task of minimizing the stuff, of clearing the home, of making way for change and new life. In fact, with everything else in the house, I'm ruthless. I clean out closets, bookshelves and kitchen drawers at least once a month. But motherhood changes you, and when it comes to getting rid of the baby items, it isn't really about the space certain materials take up; it's about holding on to what is dear.

When it came time to downsize, I told myself I could keep that one tub. It was fair to assume that some things would be too precious to part with or that there would be things I'd want to pass down to my daughters as they become mothers.

With a safety net in place, the first part was easy: I tossed all the stained onesies; the little jammies with holes in the knees; the plastic, noisy toys that entertained the babies but I never liked anyway. Then I took out the things that would completely break my heart to lose—the hospital cap, the dress, the mobile. These items are so treasured and so strongly linked to memories, that to lose them might be to give up a part of myself.

Then I looked at everything else. I was left with some really special things. There was an Easter dress that was huge and fluffy; that was more costly than any baby clothes should be; that would look darling on my future granddaughter some day. But the tulle would take up so much space in the tub, and really, my oldest daughter wore it only once. It never even fit my second daughter in the right season. Like ripping off a Band-aid, I tossed it in the giveaway pile.

Are you expecting me to say that that moment gave me freedom? That getting rid of the other in-between items was easier? It wasn't. With regret I let go of the Janie and Jack romper that both of my girls had worn for a few months. I passed along the wooden toy animals, even though they were beautiful. I did this with hesitation, and with regret even before the deed was done.

But I also did it with clarity. I realized, somehow, through tears and the haze of memory lane, that this would be my lot as a mother. To raise daughters (and sons, I imagine) will be to constantly let go.

I will have to make the choice to live fully in each season, no matter how long or short, however sweet or tumultuous, and then I will have to move on from it. I expect, the older they get, it will require even more release than the simple tossing of a toy into a pile. It will require, “I trust you," or “This is your life to live." The tangible souvenirs of motherhood will shrink, and I will need a fully exercised memory to hang on to my treasures.

So I put it into practice today. I do the hard work of letting go now, while that means only passing along a cute dress or a knick-knack, in hopes that, when the day comes, I will be able to let go in the ways my daughters need me to.