Here in Geezerville, it can be hazardous to place too much faith in our expectations. We visualize doing at 75 what we’ve mastered at 65, we assume we’ll live our days in our own home, we imagine relationships coalescing and enduring until we take a look at. But things change and disappointments loom. Sometimes, it’s just hubris that does us in; in some cases, it’s all about clinging to what's.

I was considering this last Friday while jogging neighborhood with my grandson, who’s careening toward his second birthday, and it occurred to me that my long-striding days are pretty much over. In a couple of years, I may not be able to catch The Little Guy.

Besides, in a few days he’ll be 1,500 miles away, happily ensconced together with his dad and mom in Southern California. I’m unsure when we’ll next have the ability to race.

My neighbor Joe likes to say of his grandkids, “It’s nice to determine them come and it’s nice to determine them go.” There’s certainly some truth to that particular, but I’m finding this grandpa thing to be a bit more complicated. When TLG was a baby, he was as inscrutable as any other newborn. We awaited the kid that would emerge from that cocoon. Our Friday afternoon visits have provided us with an opportunity to watch as he grew into his toddler persona — sweet, combative, curious, and demanding.

At the same time frame, I’ve observed my own transition from the nondescript stranger to a guy named “Da!” It’s a hardship on me to describe the joy that arises when TLG requests my help with a tap on the leg or demands my presence inside a tower-building project by pointing emphatically to the floor. These are gestures so endearing, yet so insistent, that I can’t help but comply. In the middle of it, I begin to realize just how much I miss those days when our very own kids needed my help.

Part of the appeal, of course, is the way toddlers permit geezers to return, if temporarily, to their own childhood. TLG invites me to revisit my youth: chasing him around the house, hide-and-seeking behind the chairs in the living room, contorting our faces to spark a giggle-fest at the dinner table.

And then there are moments when he’s completely focused on a task, and I’m riveted by his improbable, intense concentration — seized by the ineffable magic of learning. I’m i felt the same way when our own kids found that moment, but a lot time has passed that it seems completely fresh.

It’s not every joy and wonder, though. I took TLG to the zoo a couple of weeks ago and, despite his obvious excitement about the trip, the afternoon was a grind. He was clingy and distracted, uninterested in the animals; we lingered for barely an hour or so. Back at our place, he played lethargically and collapsed right into a long nap. It reminded me that, as TLG grows, our relationship can change.

My older brothers often complain that their own grandchildren barely acknowledge them as time accumulate. As one of them mentioned recently, “He makes the house with his iPad and says, ‘Papa, what’s your password?’ And that’s about it.”

Writing within the New York Times, Paula Span recounts her very own challenges as her granddaughter moved beyond toddlerdom. “Time comes in any relationship once the initial infatuation dampens a bit,” she notes. “The beloved’s behavior receives a bit annoying; the sense that you’re in accord on everything begins to erode. You find yourself sparring about stuff that never used to divide you.”

TLG and that i haven’t reached that point yet, however i wonder how the distance between us will erode the bond we’ve forged. FaceTime sessions on tiny smartphone screens are seldom revelatory; he may not even remember what “Da” looks like.

And that’s going to have to be OK. Maybe it’s an opportunity to acknowledge the inevitability of change, an opportunity to ratchet back my expectations from the ideal. I think even TLG includes a sense of this transition — and also the need to keep things in perspective. When his mom found pick him up on Friday and we were fumbling our farewells, a familiar aroma emanated from his diaper. “Here ya go, Granddad,” she said, handing him over and done with a laugh.

I cleaned him up — the final diaper change for the foreseeable future — and sent him scurrying back to his mom. It was, it occurs to me now, the perfect way to state goodbye.