You don't know what you've got 'til it's gone.

Origin

The profound truth that we often fail to appreciate something until it's lost is a sentiment as old as human experience itself, echoed in ancient proverbs and philosophical musings for centuries. But for many, this particular phrasing truly solidified its place in the modern English lexicon with the unforgettable chorus of Joni Mitchell’s 1970 hit "Big Yellow Taxi." Her poignant lyrics, "Don't it always seem to go, that you don't know what you've got 'til it's gone," struck a universal chord, encapsulating a timeless human tendency in a catchy, accessible form that became an instant cultural touchstone. While the core wisdom predates the song, it was Mitchell's musical artistry that etched these words into our collective consciousness, turning a general observation into a celebrated, widely recognized idiom.