A: Do you think we can get a raise this month?

B: It might happen, but don’t hold your breath. By the way, is your smartphone fixed?

A: Not yet. The guy from the maintenance center said he’d be here before noon, but I won’t hold my breath as well.

Note: This idiom means that one is not waiting for/should not wait for something. It often is put as an imperative — don’t hold your breath, meaning “don’t expect it; it’s unlikely to happen.” This expression in effect implies it is unwise to stop breathing until a particular event occurs, since it may never come to pass. The term appeared in the 1900s, used as mildly sarcastic humor.