of a lifetime
That is the best one can expect to ever encounter.
Synonym: once-in-a-lifetime
the opportunity of a lifetime
The privilege of a lifetime is being who you are. Joseph Campbell
Patriotism is not short, frenzied outbursts of emotion, but the tranquil and steady dedication of a lifetime. Adlai Stevenson II
The privilege of a lifetime is to become who you truly are. Carl Jung
What you see before you, my friend, is the result of a lifetime of chocolate. Katharine Hepburn
The opportunity of a lifetime is seldom so labeled. American Proverb
The opportunity of a lifetime is seldom so labeled. Albanian Proverb