I always like to buy a postcard.

Occasionally actually post them before I leave a place (ideally soon after I arrive).

Generally they arrive substantially after I get back.

Yep, same path. Arrive, get cards ASAP, usually as I walk out of the airport, give it to the hotel concierge the next morning. They will often stamp and drop it in the mail for me.

It is so much fun to watch my spawns showing me the cards they got with strange stamps and neat pictures of far away lands. I address them individually, so there are plenty to write, still fun.