What is economic life?

The three are often used interchangeably but measure different things. Economic life is the period the asset stays economically viable and produces a net benefit; it drives replacement timing, lease terms and investment decisions. Useful life is the accounting estimate used to spread the asset's cost across reporting periods under AASB 116, which requires the estimate to be reviewed each reporting period. Physical life is how long the asset can keep operating mechanically or structurally, whatever the economics.

Residual value sits alongside them: the expected market or salvage value at the end of the useful or economic life, which feeds lease residuals and disposal planning. If new evidence changes your estimate of an asset's life, accounting standards require the change to be applied prospectively, revising depreciation over the remaining life.

Lessors commonly set a lease term to a fraction of economic life so the asset still holds value at the end. Operating-style arrangements tend to run well short of it; a finance lease may run close to it. The lessor carries residual value risk on an operating lease and takes the asset back at the end; under a finance or novated lease the lessee is responsible for the residual, and in other structures the contract decides. Either way, a shorter economic life means more residual uncertainty and a higher risk margin in the pricing.

Financiers also use it in day-to-day risk management: covenants tied to usage or maintenance, impairment tests linked to remaining life, and remarketing plans. Assets with predictable economic lives and established secondary markets, such as common agricultural machinery, are easier to finance than specialised plant, which may need a shorter term or extra security. Realistic estimates help borrowers avoid mispricing and covenant breaches when structuring asset finance.

Start with manufacturer specifications, then adjust for your own usage and environment, because manufacturer figures are often optimistic. Your fleet records and industry benchmarks show what actually happens in practice. The ATO's effective life tables are authoritative for tax and cover many asset classes, though they are broad; if your use differs, you can self-assess, provided you document why the alternative is more appropriate and keep records.

A total cost of ownership approach finds the break-even point where continuing to run the asset costs more than replacing it. Quantify the drivers where you can (hours per year, expected uptime, technology refresh cycles), write down the assumptions, and review them at least annually or after a regulatory change, major repair or market shift.