Ah, yes - balance. A sweet spot. Contentment, as it were. A similar phrase: There is only one day left, always starting over (Sartre) - We have today, what are we going to do with it. But also, there's likely a tomorrow - Does what we do today impact that? To me, this is about living with purpose. One day left - but starting over (it comes again) - and so, and so we should live with purpose - your call for balance strikes me here - the need to be prepared AND be passionate. Constant preparation and worry is unsettling - unbridled passion is likely to break things - Balance, then, is key.