We cross into Oregon after 10 hours of driving – a welcome sign, seriously numb bums and the speed limit drop announce that we have officially left California, the desert, and it’s endless sun, behind. The iPhone plugged into the car stereo is playing a cached playlist from our favourite internet radio station. Dave managed to download the tunes the last time we had access to the internet, a week ago.

From the backseat, the four year old, who is holding the phone because he likes looking at the album art work, (and when you’re strapped into a five point harness all day it’s nice to feel you have control of something) asks, “What’s this song called?”

I contort myself back to glimpse the screen. Read the words out loud: “Adios to California, by John Hewitt.”

“Seriously?” says my husband from behind the wheel. He literally just passed the sign announcing the border; he dances his fingers along my arm to indicate his goosebumps-all-over reaction.

That last morning in camp as we drank our coffee and the kid kicked up his last desert storm of sand, I closed my eyes and thought about the swollen rivers, the rain coming down at home, the closet full of winter gear ready to haul out, size up, and I revelled in the sun on my bare shoulders and my dusty feet and the way the inside of my eyelids looked orange against the light cresting over the mountains into the wide desert valley.

This might be the last time I feel sun-warmed for six months, I acknowledged. Better feel it before I forget what sun on naked shoulders feels like. And I just sat with that for a moment.

Then the bustle of camp tear down was underway. Then, hours of asphalt unravelling before us. Then, this moment. Some cosmic reminder coming through the car stereo reminding us to pay attention, take note, sing along: Adios to California.

Firsts are easy to note – the awkwardness, the stumbling, the applause – we’re somehow primed to look for them, commemorate then, document them.

Lasts often slip by unnoticed.

Three weeks earlier, when we’d scanned the house and locked the door behind us, I’d mostly been thinking about coming back – how nice it would be to be greeted by a clear countertop, an uncluttered mud-room, a stack of dry firewood. I didn’t think to consider that might be the last time I’d ever be there.

I tend to bank in the permanence of things.

On the road, we encountered evacuees fleeing the Northern California wildfires. Their community ablaze, they were leaving.

“What did you take with you?” I asked a 60-something woman on the way to outwait the fires at her mother’s.

Their community was powered by propane, she said. Every home had a big tank. She watched the fire rip down the hillside, powered by 80 mile an hour winds, envelope a home with a boom as another propane tank exploded.

“That’s the funny thing,” she says, shrugging. “Nothing, really.” They looked at their home, the stuff that told the story of their life, and it was just stuff. They walked away from it all. There’s a good chance they won’t see any of it again but they drove away from the smoke and ash and flames with gratitude. They had their health, their dog, each other, their computers and personal papers. Not much more than the clothes on their backs. In the intensity of that moment, it was made clear to her that she had everything she needed. She closed the door and walked away, with no way of knowing if she’ll ever see anything again.

A gratitude practice is something often recommended in the kind of books that vaguely irritate me for being cloyingly wholesome and advice-giving. How much more of an attitude shift would it give me, not to give thanks around the dinner table or in my notebook before I go to bed or once a year at the altar of the turkey, but instead to pause in the middle of a moment and think, this could be the last time.

It’s a way of thinking that has pushed me past reluctance and off the dock into the lake, out of my warm bed and outside to watch a star show, to sit a bit more patiently with the kid. “One day you won’t want to sit on my lap anymore,” I told him, by the campfire, this trip, his legs almost dangling on the ground. “And I won’t have known that the last time was the last time. So I’m just sitting here and enjoying this.”

The last time won’t necessarily announce itself – more often, it has a subtlety that the firsts don’t have – it will just come and go and later I’ll realise, hey, hang on, I didn’t realize, I don’t know that I was ready for that.

And the music would sing: pay attention sister. It’s called impermanence. If you’d been listening closer, you would have realized all along. And sung your heart out.