Because I see my postie regularly, and want him "on-side", as I said. When I was working, I had stuff delivered to the office post-room, and always bought them a big box of chocolates for Xmas.
Everybody else just gets a "thank-you", except for carol singers (and trick-or-treaters) who usually...
If so, what's the going rate? Is it worth it to keep him / her onside?
And what's reasonable to give carol singers? Is it more for a group? Anybody seen any?
I've lost touch with these things...