“I could improve your ultimate financial welfare by giving you a ticket with only 20 slots in it so that you had 20 punches—representing all the investments that you got to make in a lifetime. And once you'd punched through the card, you couldn't make any more investments at all.”
The Twenty-Slot Punch Card
Charlie Munger relays the line in his 1994 talk at USC Business School, introducing it as something Buffett tells MBA students. No Buffett primary transcript carrying this exact phrasing has been located; Munger’s quoting of it is the strongest textual source.
Reading the twenty slots as a rule about saying no is half the picture. The other half is what a finite ration commits you to when a slot does come off the card: load up, not nibble. Buffett’s own counterweight, from the 2009 letter to Berkshire shareholders, is “Big opportunities come infrequently. When it’s raining gold, reach for a bucket, not a thimble.” Refusal earns its keep only because the bucket years are rare; if every year were a bucket year, the punch card would be the wrong tool.
Most calendars look like the opposite system: a thousand small punches taken on autopilot, with no slot held in reserve for the day the gold actually rains.