The Pareto Principle (80:20 rule) is well known in business.
20% of what is done will give you 80% of the results.
80 % of what is done will produce only 20% of the results.

20% of the time you spend will yield 80% of the result
And
20% of your clients/ customers will yield 80% of the turnover.

… and so on.

My observation is this…
in the modern age, it’s now shifting towards a 97/3 rule – not quite as catchy a title, but there we have it.
Whether it’s 80/20 or 97/3, the real issue is in knowing what the 3% (or 20%) of productive activity is.

What’s yours?