Spare Parts Know How

Spare Parts Inventory Management Training

  • Log-In
  • Individual
    • Open Access
    • Practitioner Toolkit
    • Compare Options
  • Organization/Team
    • Foundations for Teams
    • Foundations Playbook
    • Operations Playbook
    • Enterprise Access
    • Compare Options
  • Targeted Improvement Programs
    • Capability Programs
    • Advisory Support
    • Inventory Optimization Software
    • Data Management Services
  • Resources
    • The Spare Parts Decision Framework
    • Spare Parts Capability Playbooks
    • Roadmap for Spare Parts Decision Capability
    • Site Capability Assessment
    • Spare Parts Management Checklists
    • Obsolescence Risk Calculator
    • Criticality Assessment Tool
    • ROP/ROQ Calculator
    • Last Time Buy Calculator
    • Books
    • Practitioner Playbook Digital Library
  • 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 Foundations 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 individuals this playbook is available via the Practitioner Toolkit.

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 the Practitioner Toolkit
The complete spare parts management toolkit for practitioners.

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 +25 Years of Spare Parts Management Know-How. No email required. No data collection. Just pure know-how.
Read more...

Practitioner Toolkit

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

Foundations Playbook

Team-based access to the core principles and decision logic required for effective spare parts management.

Read more...

Operations Playbook

Team-based access for organizations improving policy, optimization, controls, data, storeroom practices, and implementation.
Read more...

Foundations for Teams

This facilitated program helps participants discuss the principles, challenge assumptions, and develop a common language and understanding of spare parts decision-making. Read more...

Enterprise Access

Combine resources and SparePartsKnowHow support according to the capability your organization needs to build. Read more...

Latest Blog Posts

  • AI Spare Parts Technology Won’t Fix Weak Decisions
  • Twenty-Five Years of Better Spare Parts Decisions
  • The Cost of Inconsistent Spare Parts Decisions
  • Spare Parts Capability Cannot Reside in One Person
  • Which Spare Parts Playbook is Right for You?
  • Email
  • LinkedIn
  • YouTube

Copyright © 2026 IPIAIGHT PTY LTD.