Useful Life

The useful life (UL) of an asset is the estimated length of time during which the asset is likely to be able to deliver a satisfactory level of service.

International Infrastructure Management Manual

The International Infrastructure Management Manual states that "useful life" may be expressed as either:

  1. The period over which a depreciable asset is expected to be used, or
  2. The number of production or similar units (i.e. intervals, cycles) that is expected to be obtained from the asset.

CPA Australia valuation and depreciation guide

The CPA Australia valuation and depreciation guide suggests that there is an asset management/engineering definition of useful and an accounting one.

  1. Engineering Definition - The period from original commissioning to the time of decommissioning, including a number of expected major renewals.
  2. Accounting Definition - The period in which the asset is expected to be available for use or the number of production or similar units expected to be obtained by the entity.

General Notes

The useful life of an asset is not necessarily equivalent to its physical life or economic life, a number of other factors may result in an assets useful life being reduced, including:

  • Obsolescence
  • Changes in community expectations
  • Increased demands on capacity
  • New legal requirements

Typical Useful Lives

The useful life of most assets will depend on a wide range of environmental factors, but it is usually necessary to adopt a standard useful life for a range of asset types for asset management and accounting purposes. It would make life much easier if the state or federal governments published a list of default asset useful lives for Councils to use in the absence of better information, but with the notable exception of South Dakota in the United States, a quick internet search seems to suggest that this isn't a high priority for state governments around the world.

The table below is LGAMs attempt to compile a list of realistic asset useful lives.

Asset Type Typical UL Range
Asphalt Footpath 30 years 20-50 years
Asphalt Overlay 20 years 20-25 years
Backhoe 6 years 5-7 years
Boardwalk 30 years 25-30 years
Bollard 20 years 15-30 years
Box Culvert 90 years 80-100 years
Brick Paved Footpath 50 years 30-80 years
Bridge 80 years 25-100 years
Building Envelope 60 years 45-75 years
Building Fire Services 40 years
Building Fitout 30 years 20-45 years
Building Mechanical Services 30 years 25-35 years
Bus Shelter 20 years 20-40 years
Computer 3 years 3-4 years
Concrete Floor 100 years
Concrete Footbridge 80 years 25-200 years
Concrete Footpath 60 years 20-120 years
Concrete Road Bridge 90 years 30-100 years
Crane 10 years 5-10 years
Culvert 65 years 50-80 years
Dam 60 years
Fence 10 years
Flagpole 40 years 20-60 years
Floor Coverings 20 years 5-40 years
Front End Loader 7 years 5-10 years
Grader 10 years 5-10 years
Gravel Footpath 12 years 5-50 years
Gravel Resheet 12 years 5-20 years
Guardrails 20 years
Headwall 80 years 70-100 years
Kerb & Channel 60 years 20-120 years
Lifts & Transport Services 25 years
Litter Bin 20 years 20-30 years
Mower 7 years 5-10 years
Park Bench 25 years 15-50 years
Passenger Vehicle 6 years 2-10 years
Playground Equipment 15 years
Pumping Station 50 years
Reinforced Concrete Stormwater Pipe 100 years 80-120 years
Retaining Wall 25 years
Road Formation 1000 years 150-∞ years
Road Pavement 80 years 20-120 years
Roller 6 years 5-7 years
Roof 50 years 15-90 years
Runway 30 years
Service Reservoir 50 years
Sewer Maintenance Hole 80 years
Sewer Pipe 75 years 65-80 years
Skate Park 50 years 50-80 years
Solar Panel 30 years 25-40 years
Splitter Island 50 years 50-70 years
Sprayed Seal 15 years 12-30 years
Steel Footbridge 60 years 25-100 years
Stormwater Pipe 60 years
Stormwater Pit 90 years 70-150 years
Street Lighting 30 years 20-50 years
Timber Decking 30 years 15-60 years
Timber Footbridge 40 years 25-100 years
Tractor 8 years 5-10 years
Traffic Sign 15 years 10-30 years
Traffic Signals 25 years 15-40 years
Treatment Plant 50 years
Truck 7 years 5-10 years
Two Coat Seal 15 years 10-50 years
Valve 10 years
Water Meter 10 years

Related Pages

External Links & References

  1. Infrastructure Asset Useful Lives - 2009 (LGA.SA)
  2. Infrastructure Asset Useful Lives - 2014 (LGA.SA)
  3. Boroondara City Council Asset Management Plan for Roads
  4. South Dakota Municipal Asset Useful Life Table
  5. Road Safety Engineering Risk Assessment Part 4: Treatment Life for Road Safety Measures (Austroads)
  6. Lifecycle Cost Guidelines for Sport and Recreation Facilities (Western Australian Department of Sport Recreation)
  7. Tweed Shire Council Drainage Assets Management Plan
  8. Asset Lives - Felix Schrodinger's Blog
  9. Levels of Service & Asset Lives - Felix Schrodinger's Blog
  10. The Gold Book (SA Department of Education and Child Development)
  11. Standard Life Comparison Roads and Stormwater
  12. Google Search
  13. CPA Australia valuation and depreciation guide

Notes (Edit)

Maximum Theoretical Useful Life

The Assets Section has been discussing the concept of a maximum theoretical useful life recently. Below is an attempt to explain the advantages of adopting the maximum theoretical useful life of an asset as its useful life.

  • Significantly reduces the likelihood of over-depreciating an asset.
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