Waste Not, Want Not Meaning

(idiomatic) If one is not wasteful then one will not be needy.

Example: 1872, Thomas Hardy, Under the Greenwood Tree. ch. 8:
  There were, besides, some little pleasures in the shape of helping her to vegetable she didn't want, and when it had nearly alighted on her plate taking it across for his own use, on the plea of waste not, want not.
1910, Edith Nesbit, The Magic City, ch. 2:
  â€œThey take the cocoa-nuts to the town kitchen,” said the captain, “to be made into cocoa-nut ice for the army breakfast; waste not want not, you know.”
2006 July 9, Richard Corrigan, "Fish tales," Sunday Times (UK) (retrieved 5 July 2008):
  I'm a believer in “waste not, want not”, and we roast our leftover bread, finely sliced and brushed with olive oil, in a low oven.