Why it was said

JL Collins gives the whole of The Simple Path to Wealth in this line in the introduction. The book began as letters to his daughter, who did not want to think about money, and the sentence is what he most wanted her to keep.

What it actually means

Everything else in personal finance is detail on these three clauses, and most of the detail is sold by people who profit from complexity. Collins's version has no product in it: the surplus goes into a low-cost index fund and stays there through every crash, and debt is treated as an emergency rather than a tool. The sentence is short because the path is, and the difficulty is not understanding it but doing it for twenty years.

How to use it

1. 1Write your three numbers: what you earn, what you spend, what is left, and make the third one automatic.
2. 2Treat any new debt as an emergency to be cleared, not a normal part of life.