Spare Parts Know How

Spare Parts Inventory Management Training

  • Log-In
  • Playbooks
    • Foundation Playbook
    • Operations Playbook
    • Practitioner Playbook
  • Teams + Companies
    • Foundations for Teams
    • Team & Enterprise Access
    • Inventory Optimization Software
    • Data Management Services
  • Expert Advisory Support
  • Resources
    • Open Access
    • Practitioner Playbook Digital Library
    • Books
    • Obsolescence Risk Calculator
    • Criticality Assessment Tool
    • ROP Calculator
    • Playbook Selection Tool
  • Contact
  • About
    • Past and Current Users
    • Testimonials
    • FAQs
    • Phillip Slater

How do we determine spare parts criticality?

You are probably asking this because too many parts have been classified as critical, or because no one is confident that the current criticality ratings are accurate.

The reality is that not every important spare part is critical.

In fact, items that are critical for a machine to operate are not necessarily required as critical inventory.

This is counter-intuitive but also true.

And that distinction matters.

If everything is called critical, then the label stops being useful.

Criticality should help you make better decisions about stocking, review frequency, supplier management, maintenance support, and risk exposure.
 


The Common Mistake

 
The common mistake is allowing criticality to become an opinion.

In many organisations, parts are classified as critical because:

    the equipment is important,
    maintenance says the part is needed,
    the part has a long lead time,
    the part is expensive,
    the part has caused a problem before,
    no one wants to take the risk of saying it is not critical.

Each of these factors may be relevant, but none of them automatically makes the part critical.

A part is not critical simply because it is expensive.

Nor is it critical simply because it belongs to critical equipment.
 


What a Better Decision Requires

 
A better criticality decision separates consequence from emotion.

That means considering questions such as:

    What happens if the part fails and no spare is available?
    Does the failure stop production, reduce capacity, create a safety risk, or breach compliance?
    Is the item required to restore equipment function?
    Can the part be repaired, sourced quickly, substituted, or bypassed?
    Is the consequence based on current operating conditions?
    Is the classification consistent across similar parts and assets?

Criticality should be a decision input, not a label applied casually.

Used properly, it helps determine which parts deserve attention, which parts require stronger controls, and which parts may not need to be stocked at all.
 


Where This Is Covered

 
This topic is covered in the Foundation Playbook, which addresses not only why criticality matters and why it is often misunderstood, but also a comprehensive, yet easy to apply framework for determining criticality.

For teams, Foundations for Teams helps create a shared language so criticality is not driven by the loudest voice in the room.
 


Choose Your Next Step

 
Explore Foundations
Understand the principles behind better spare parts stocking decisions.

Enquire about Foundations for Teams
Build a common decision language across the people who influence spare parts outcomes.
 

Join a Global Community

Trusted by:
+20,000 professionals in
+130 countries
See a sample of companies HERE

Open Access

Open Access to 20 Years of Spare Parts Management Know-How. No email required. No data collection. Just pure know-how.
Read more...

Foundations Playbook

Our Foundation Playbook is designed to answer question relating to the essential knowledge, tools, and techniques for effective spare parts inventory management.

Read more...

Operations Playbook

The Operations Playbook is the decision support resource for people who need to go beyond the basics and perhaps even revolutionize their company’s systems and approach.
Read more...

Practitioner Playbook

The Practitioner Playbook provides the most complete access to decision support resources, tools, and advanced content.
Read more...

Foundations for Teams

Foundatiosn for Teams is a live, online, interactive, team-based delivery of our Foundations Playbook content designed to provide your team with a common understanding of the basics of spare parts inventory management. Read more...

Enterprise Access

For organizations that need broader access across teams, sites, or functions. Read more...

Latest Blog Posts

  • The Foundations Playbook is Now Live
  • A Shift in How Spare Parts Knowledge Is Delivered
  • Doing the Hard Things Makes Spare Parts Management Easier
  • Why Every Plant Thinks Its Spare Parts Challenges Are Unique (and Why They Aren’t)
  • Avoiding Survivorship Bias in Spare Part Procurement: From Efficiency to Resilience
  • Email
  • LinkedIn
  • YouTube

Copyright © 2026 IPIAIGHT PTY LTD.