Franklin contrasts the one-off cost of building a chimney with the continuing expense of supplying it with fuel. The point is that acquiring something may be relatively easy compared with paying for its use and upkeep over time. A possession that appears affordable at the outset can create recurring costs that eventually exceed the original expense.

The saying therefore encourages attention to the full cost of ownership rather than the purchase price alone. Its principle applies more broadly to property, equipment and other commitments that require continuing expenditure. Franklin’s wider lesson is that financial prudence involves asking not only whether something can be obtained, but whether it can be maintained without creating an unsustainable burden. The proverb distinguishes between the cost of acquisition and the often larger responsibility of keeping something in use.