“Do”-to-“do” delivery

The answer to the crossword question “Do-to-do” delivery is the word “scale“. The clue is a play on words, as “scale” can refer to both the musical scale and a scale used for weighing. “Do” is a note on the musical scale, and “do-to-do” could be interpreted as going up or down the scale. In the context of weighing, a delivery measured by a scale would be a precise “do-to-do” transfer of goods. Therefore, the answer to the crossword question is “scale“.