Ever notice how no matter how big your suitcase is, you’ll somehow manage to fill it? Or that bigger shopping carts lead to buying more stuff? This is all thanks to Parkinson’s Law, a principle that applies to far more than you might expect.

Originally formulated by Cyril Northcote Parkinson in 1955 as “Work expands so as to fill the time available for its completion,” this principle has been observed across countless domains:

  • Storage spaces: Closets, garages, and drawers always seem to fill up regardless of size
  • Digital storage: Hard drives inevitably reach capacity, no matter how many terabytes
  • Highways: Adding more lanes doesn’t reduce traffic - it just invites more drivers
  • Spending: Most people’s expenses somehow always match their income
  • Meetings: They almost always consume their full scheduled time, even when the agenda is completed early

In computing, this manifests as Wirth’s Law: “Software expands to fill the available resources.” That’s why your computer doesn’t necessarily feel faster despite having exponentially more processing power than machines from 10 years ago.

The practical takeaway? If you want to spend less at the grocery store, grab the smaller cart. If you want to pack lighter, bring a smaller suitcase. And if you want a meeting to end sooner, schedule it for less time.

What other examples of Parkinson’s Law have you noticed in your life?