GRAMMAR DETAIL

〜ついでに

while one is at it · on the occasion of ...

Indicates taking the opportunity provided by a main task to do something else as well.

Examples

駅前へ買い物に行くついでに手紙を出した。

I mailed a letter while I was out shopping near the station.

図書館へ行くついでに本を返した。

Since I was going to the library anyway, I returned a book.

散歩のついでに郵便局へ寄りました。

I stopped by the post office while I was out for a walk.

Structure: ついでに after a dictionary-form or ta-form verb, or a noun plus の, adds a secondary task using the opportunity provided by a main one.
Basic usage: 駅前へ買い物に行くついでに手紙を出した。 describes mailing a letter as an extra task during a shopping trip.

The main task and the extra task
- In 買い物のついでに手紙を出す, shopping is the main task. Reversing it to 手紙を出すついでに買い物をする makes mailing the letter the occasion, changing the relative importance of the two tasks.