This is the most important key principle in effectively managing a property and a LTMP . You need to understand what a cycle is in the context of an item and an event and types of activities.

A structural asset item has 1 life cycle BUT more than 1 type of maintenance cycles and events.

Life cycle

An item’s Life cycle  must be understood from its actual life, to its useful life 

Actual LIFE CYCLE is:

  • The time interval from commencement an asset  to termination/decommissioning , which can exceed the economic life of an asset. There is a specific international accepted life expectancy for each structural asset.
    The period from the acquisition of the asset to the time when the asset, while physically able to provide a service, ceases to be the lowest cost alternative to satisfy a particular level of service. The economic life is maximized when it’s equal to the physical life, however obsolescence will often ensure that the economic life is less than the physical life
  • The calculation is precise not ‘s guesstimate:EUL
    • Value calc: EUL = capital cost or CRC (current replacement cost) > Risk cost
    • Cost calc: Marginal cost < EAC(equivalent annual cost)
  • Practical application: You endeavor to maximize an item’s life, using the expected life as a norm. The actual useful life will be subject to adherence to maintenance and resulting degradation pattern. The ideal is to replace an item only when above ratios are negative. The 1st relating to the value vs failure risk and the 2nd to the cost between the existing and replacement asset.

Maintenance cycle

The total cost of an asset throughout its life including planning, design, construction, acquisition, operation, maintenance, rehabilitation and disposal costs.

A maintenance cycle is the maintenance activities that is specified by the manufacturer or necessitated by owner or goal.  These activities vary in timing and detail.

For insight let’s use a vehicle as a point in case.

  • There is routine activities such as cleaning, checking, monitoring and adjusting (Monitor indicator on dashboard, adjusting pressure in tyres, oil, break fluid…)
  • Then there is formal maintenance schedules at specific  time/or events                          (every 1500km or once a year…)
  • Then you have repair , wear & tear & part replacement  done ad hoc, event based or via a maintenance plan 

A property asset is similar.

You have different activities done a different time patterns (or cycles). These combined set of activity cycles is the essence a maintenance plan.

This is a critical understanding!

  • As an activity such as renew paint on a wall is done in 7 to 10 year cycles, need the other activities also be detailed in cycle dimensions which some is annual or non annual cycles. Then there is also a failure cycle, which might seem to be random…it’s not

The only random event is a specific interventions such as vandalism or misuse or resultant consequence of another items failure.

Lets consider a maintenance plan for a wall.

  • Standard activities
    • Annual cycle: inspect & repair wall for structural and operational deterioration(foundation integrity, damp, cracks, moss…
    • 7 year cycle: renew paint works & water proofing
  • Life extension activities
    • 3 yearly cycle: clean wall and do spot repairs where paint has been degraded by elements. This restores longevity and enable renewal in 10 year cycles. instead of 7 year cycles.
    • Then there may be unique activities that is enacted to achieve as certain life extension benefits and improving environmental factors such as root removal, tree trimming, paving/sealing surrounds to reduce degradation.
  • Lets use numbers to interpret the maintenance cycles
    • Standard activities will ensure adherence to specifications and thus normalize aging(EUL), while extension activities improve the margins and benefits.
      •  Non adherence increase the failure risk(risk cost)  and increase of extend of repairs thus decreasing the risk factor and marginal cost factor and ultimately the EUL of an item.
      • adherence ensure normalized aging and thus propensity to achieve the EUL.
      • Extending renewal cycles and improving environmental factors directly reduce marginal cost level and reduce cost of failure risk thus improving the EAC ratio and thus EUL.


By understanding the difference between the life cycle and maintenance activity type cycles can you determine what needs to be done when to maximize an assets life expectancy and minimize its life cycle cost.

If you are not able to calculate this life cycle metrics, then you are guessing and believe you are right.

As they say believe is a wonderful thing.

………..if funding is unlimited.