The Banana Principle: If you buy bananas or avocados before they are ripe,

The Banana Principle: If you buy bananas or avocados before they
are ripe, there won't be any left by the time they are ripe. If
you buy them ripe, they rot before they are eaten.

Related:

• Cherry ripe, ripe, ripe, I cry, Full and fair ones,
  come and buy! If so be you ask me where They do grow...
• And so from hour to hour we ripe and ripe, And then from hour to hour we rot and rot;
  And thereby hangs a tale. -- William Shakespeare (1564...
• He became mellow before he became ripe. --
  Alexander...
• Pauca sed matura.
  [Few but excellent (or ripe).] --...
• Fast Ripe, Fast Rotten.
  Japanese...
• A good head and good heart are always a formidable combination.
  But when you add to that a literate tongue or pen,...
• When you get to be the age of George Burns,
  it is unwise to buy green bananas...
• She has a really opulent body;
  just ripe for dissecting...
• The aristocrat is the democrat ripe and gone to seed.
  Ralph Waldo Emerson (1803...