What's the difference between ABC and VED classification for spare parts?

ABC ranks parts by dollar value — which ones represent the biggest share of your inventory spend. VED ranks parts by criticality to operations — Vital, Essential, or Desirable. Used together, they stop you under-stocking a cheap-but-critical part that ABC alone would rank low.

How do I know if a spare part is "critical"?

Ask whether the line actually stops without it, and how long a genuine replacement takes to source. A cheap part that's slow to get and stops production is more critical than an expensive part available locally overnight.

Is a formal spare parts classification system worth it for a small factory?

A full matrix isn't necessary at 5 to 50 machines. The three-question version — does it stop the line, how slow is it to source, how often does it actually fail — captures most of the benefit without the overhead of a formal system.

Which spare parts should you actually stock? A criticality approach for a small factory

Taylor Scott, Victorian safety practitioner, Ardmor Operations — Last updated 23 July 2026·2 min read

The problem with stocking spares by price

The instinct is to keep the expensive parts on the shelf and order the cheap ones when you need them. For a lot of factory spares, that's backwards. A $15 seal that takes three weeks to arrive and stops the whole line is a bigger risk to leave as "order when needed" than a $2,000 spare motor you could get overnighted from a local supplier.

Criticality, not cost, is the real question

Reliability engineering has a well-established way to think about this properly. Ranking parts by dollar value alone — an "ABC" analysis, where A-items are the small share of parts that account for most of your inventory spend — tells you where your money sits, but not where your risk sits. Pairing it with a criticality ranking, sometimes called VED, fills that gap:

Vital — the line stops without it, and it's genuinely slow or hard to source
Essential — it matters, but there's a workaround or a faster path to a replacement
Desirable — worth having, but its absence for a few days won't actually hurt you

A cheap part can still be Vital. An expensive part can still be Desirable. Combining value and criticality gives a far more honest stocking decision than either measure alone.

A simple version for a 5-to-50-machine site

You don't need a formal matrix to get most of the benefit. For each critical machine's key wear parts, ask three questions:

If this fails, does the line actually stop — or is there a workaround?
How long would it genuinely take to get a replacement — a local supplier, or a three-week import?
How often does it actually fail, based on your own maintenance history — not the manufacturer's optimistic estimate?

A part that's Vital and slow to source earns a spot on your shelf regardless of price. A part that's Desirable and available locally within a day doesn't need to sit in inventory tying up cash.

What this looks like in practice

Bearings, seals and belts for your highest-use, hardest-to-source machines: stock them
Anything available from a local supplier within a day or two: don't stock it, just know exactly where to get it fast
Anything that's failed more than once in the past year: it's earned its place on the shelf, whatever it costs

How Ardmor helps

When a work order is raised against a piece of equipment in Ardmor, the system already knows which parts are linked to that machine — pulled from your actual equipment register, not a generic parts catalogue — and flags anything running low. The "do we actually have the seal" question gets answered before a technician is standing at the machine, not after. A parts register is one register in a wider workplace safety system — the same spine that holds your plant, training and incident records.

This article is general information for Victorian manufacturers, not legal advice. Last updated: 19 July 2026.