expression
no matter what it is; in every case; whatever the matter
Fixed expression meaning 'in any matter' or 'whatever the case may be'. Often used to introduce a general statement or habitual reaction.
何事につけ、準備が大切だ。
No matter what it is, preparation is important.
彼は何事につけても文句を言う。
He complains about everything, no matter what it is.
Similar meaning 'in everything' or 'at every opportunity', but 何事につけ is slightly more formal and less common in casual speech.
Combination of 何事 (what thing, everything) + につけ (whenever, in the case of). The につけ part is a classical conditional form of 付く, now used in fixed expressions.