Time
See also: The Future, The Past
Times Like These 
Precious Moments
Then and Now
Better Days
Every Once in a While
Through the Years
Running out of Days
Time and Time Again
Time is but the stream I go a - fishing in Henry David Thoreau
Lose an hour in the morning, and you will spend all day looking for it Richard Whately
A moment of time may make us unhappy forever John Gay
One today is worth two tomorrows Benjamin Franklin
Time is the wisest of all counselors Plutarch
All the treasures of Earth connot bring back one lost moment French proverb
Dost thou love life? Then do not squander time, for that's the stuff life is made of. Benjamin Franklin
The happier the time, the more quickly it passes Latin proverb
We do not remember days, we remember moments Cesare Pavese
Every second is of infinite value Johann von Goethe
Short as life is, we make it still shorter by the careless waste of time Victor Hugo
I wish I could stand on a busy street corner, hat in hand, and beg people to throw me all their wasted hours Bernard Berenson
They also serve who only stand and wait John Milton