This reflects that any estimate of fair value is just that: an estimate, not a precise figure, so the margin of safety provides a much-needed cushion against errors and misfortunes.

And every year, like some sort of magic clockwork, it does more and more for less and less, bringing the marginal costs of technology in the units that we individuals consume closer to zero.

Product/market fit means that the cost of acquiring a new customer is less than the marginal profit we make from that customer.

However, the objective of investment (in general) is not to buy at fair value, but to purchase with a margin of safety.

The farther down one goes in the income distribution, however, the closer the correlation between income and happiness; this is an implication of diminishing marginal utility of income.