ついでに details

Examples

while you're at it / taking the opportunity — a second, minor action piggybacks on a trip or effort already being made for the first

郵便局ゆうびんきょくに行いくついでに、コンビニにも寄よってきた。

yuubinkyoku ni iku tsuide ni, konbini ni mo yotte kita.

While I was headed to the post office, I swung by the convenience store too. casual

出張しゅっちょうのついでに、大学だいがく時代じだいの友人ゆうじんに会あってきました。

shucchou no tsuide ni, daigaku jidai no yuujin ni atte kimashita.

I met up with a friend from my university days while I was on my business trip. neutral

掃除そうじをしたついでに、いらないものも捨すてた。

souji o shita tsuide ni, iranai mono mo suteta.

Since I was already cleaning, I threw out some things I didn't need too. casual

会議かいぎのついでに、新あたらしい支店してんの様子ようすも視察しさつしてまいりました。

kaigi no tsuide ni, atarashii shiten no yousu mo shisatsu shite mairimashita.

While attending the meeting, I also took the opportunity to inspect the new branch. formal

Formation

plain clause + ついでにattaches to plain clause
{N}のついでにattaches to noun

Notes

ついでに marks the errand already being made for its own sake; the MAIN clause is the free
extra action riding along on it. Swapping which clause carries ついでに flips which one reads
as the planned trip and which as the afterthought.

Related patterns

Similar

てから
Both order two actions, but てから just welds a strict sequence with no comment on effort (歯[は]を磨[みが]いてから寝[ね]る — a plain precondition), while ついでに frames the second action as free-riding on a trip already being made for the first (歯医者[はいしゃ]に行[い]くついでに、本屋[ほんや]にも寄[よ]った — the bookstore cost no extra trip); swap ついでに in where the second action DID require its own dedicated effort, and it misleadingly downplays it.