First wine trip abroad, everything that went right (and one thing that didn't)

Our first proper wine trip overseas, and I want to save the next person our one mistake.

Right: fewer stops, longer visits. Three tastings a day, each unhurried, beat the 'five in a day' plan we almost booked.
Right: a local SIM + offline maps. Cellar doors hide down farm tracks.
Right: shipping arranged BEFORE we fell in love with bottles we couldn't carry.

Wrong: we drove to a famous estate without booking, assuming walk-ins were fine. They weren't. Turned away at the gate. Always confirm the appointment policy, even the ones that 'seem' casual.

What's the rookie mistake you only made once?