Depreciation methods, useful lives and idle capacity

Depreciation is one of the largest recurring non-cash charges for asset-heavy manufacturers, so mechanically copying tax rates, pausing depreciation during shutdowns, or leaving stale useful-life estimates in place directly misstates profit, asset carrying values and the depreciation trend that lenders and investors use to judge capex adequacy and asset age. Reduced-shift and idle-capacity situations are common across the region in cyclical or seasonal manufacturing (textiles, food processing) and are a frequent blind spot: continuing to depreciate correctly is necessary but not sufficient - failing to also test for impairment when utilization drops structurally can leave assets materially overstated on the balance sheet.

Does depreciation continue through idle or reduced-shift periods (unless units-of-production output is genuinely nil), rather than being paused? Is straight-line still the most faithful method, or would units-of-production better reflect consumption for specific lines? Are book useful lives simply mirroring tax depreciation rates rather than a genuine economic-life estimate?

1. Begin depreciating an asset from the date it is available for use (ready and in the location/condition intended by management), regardless of whether it is actually operating yet.
2. Continue depreciating on the chosen systematic basis throughout idle or reduced-utilization periods (e.g. a single shift instead of three, a mothballed line) - depreciation is not suspended merely because an asset is temporarily not in active use, unless the units-of-production method is used and output for the period is genuinely nil.
3. At each financial year-end, review the depreciation method to confirm it still reflects the pattern in which the asset's economic benefits are consumed (straight-line vs units-of-production vs another systematic method) - do not simply default to a method chosen only because it matches tax depreciation rates.
4. At each financial year-end, review useful life and residual value estimates against actual usage patterns, technology change and maintenance history; if either has changed significantly, revise the estimate.
5. Apply any change in method, useful life or residual value prospectively as a change in accounting estimate (adjust current and future depreciation charges) - never restate prior periods for this.
6. Where utilization has fallen significantly (e.g. running one shift instead of three, extended idling of a line) treat this as a potential impairment indicator and perform an impairment assessment (comparing carrying amount to recoverable amount), separate from and in addition to continuing depreciation.
7. Document the basis for tax-versus-book life differences so that using tax rates for statutory books (rather than economically-based book lives) is a deliberate, disclosed exception rather than a default.

Measurement basis: PP&E subject to depreciation is measured at cost (or revalued amount) less accumulated depreciation less accumulated impairment losses; the depreciable amount (cost/revalued amount less residual value) is allocated systematically over the useful life. What's included: depreciation continues through idle, low-utilization and shutdown periods under time-based methods (straight-line, reducing balance); under units-of-production, the charge is based on actual output/usage and can genuinely be nil only if output is nil. Excluded: land is generally not depreciated (unless it has a limited useful life, e.g. a quarry); assets held for sale under the relevant standard cease to be depreciated. Re-measurement/review trigger: useful life, residual value and depreciation method are reviewed at least at each financial year-end and adjusted prospectively for any change in estimate; separately, a drop in utilization, market value, physical damage, or adverse changes in the business/technology environment are impairment indicators that trigger a recoverable-amount test (fair value less costs of disposal vs value in use) irrespective of the annual estimate review.

Disclose: depreciation method(s) used and useful lives (or rates) by class of asset; the depreciation charge for the period and accumulated depreciation at period end; gross carrying amount and accumulated depreciation reconciliation (additions, disposals, depreciation, impairment) for the period; any impairment losses (or reversals) recognized on idle or underutilized assets, and the assumptions/recoverable amount basis used; the effect of any change during the period in estimated useful life, residual value or depreciation method (as a change in accounting estimate) on current and expected future periods.

• Adopting tax depreciation rates as the book useful lives without an independent economic assessment of actual consumption pattern
• suspending or reducing depreciation during temporary shutdowns, shift reductions or seasonal idling when the asset remains available for use
• never revisiting useful lives or residual values despite clear evidence of changed usage intensity, technology obsolescence or extended/shortened actual asset life
• treating reduced utilization purely as a depreciation policy question and failing to also consider it as an impairment indicator requiring a separate recoverable-amount test
• switching depreciation method opportunistically to manage reported profit rather than because the pattern of consumption has genuinely changed.