Worth it: the old towel (rivers exist, and so do hotel-white towels you must not use). A long line — 15 feet of freedom turns any empty ballfield into an off-leash morning without breaking a single rule. Their own water bowl, because trough-sharing is a dice roll. One unwashed t-shirt of yours, for the hotel bed. And double the poop bags you think you need, because the person who runs out at the trailhead is the person everyone remembers.

Not worth it: the travel water-bottle-bowl contraption (a bowl and a bottle you already have do the same job), the brand-new toy bought for the trip (they want the ratty one from home; comfort doesn’t come in packaging), and the full bag of food when a portioned zip-bag per day weighs a third as much and survives the trunk better.

The real trick is packing the routine, not the stuff. Same bowl, same bed-blanket, same before-sleep walk. A dog with three familiar anchors treats a new city like an extension of home. A dog with ten new gadgets and no routine treats a Tuesday like an emergency.