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one-by-one; separately
every single; each and every; without omission; fully; in detail
いちいち聞かないでよ。
Don't ask about every little thing.
いちいち聞かなくても自分で調べてください。
Please look it up yourself instead of asking every time.
いちいち気にしていたらきりがないよ。
If you worry about every little thing, there's no end to it.