Smart Spare Parts Strategy: How to Prioritize What Your Plant Really Needs

When a production line goes down, every second counts. Yet too many facilities treat spare parts as an afterthought—leading to costly delays, excessive overnight shipping fees, and production losses that dwarf the price of the part itself. A smart spare parts strategy helps you avoid these headaches by ensuring you have the right parts on hand when you need them, without tying up unnecessary capital in shelves full of “just in case” items.

Here’s how to prioritize what your plant really needs.

Why a Spare Parts Strategy Matters

Downtime is expensive. Studies show the average cost of unplanned downtime can run thousands of dollars per hour, depending on the industry. But having every possible spare on hand isn’t realistic. A targeted strategy balances two priorities:

• Availability: Critical parts are immediately accessible when needed.
• Efficiency: Inventory investment is limited to the components that matter most.

Step 1: Classify Your Equipment

Start by creating an inventory of your drives, PLCs, HMIs, motors, and other automation hardware. Classify equipment by:

• Criticality – How essential is this asset to production?
• Failure History – Which components fail most often?
• Lead Time – How quickly can you source a replacement if it fails?

A legacy drive that controls a bottleneck process, with an 8-week lead time, should rank higher than a modern HMI with next-day availability.

Step 2: Identify Critical Spares

Not all parts are equal. A critical spare is one that:

• Has long or unpredictable lead times
• Comes from an obsolete or discontinued product line
• Causes significant production loss if it fails
• Is subject to high tariff costs or import delays

Drives, PLC CPUs, and unique communication modules often make this list. For less critical items like cables or fuses, a leaner inventory may suffice.

Step 3: Balance Stocking vs. Sourcing

Ask three questions for each part:

1. What happens if it fails? (hours of downtime, safety concerns, lost orders)
2. How long will it take to replace? (in-stock locally, or 12 weeks overseas?)
3. Can it be repaired instead of replaced?

If a repair can be turned around quickly, you may not need to stock that item. But if a failure would halt a production line for weeks, it’s worth keeping at least one spare on your shelf.

Step 4: Use Data, Not Guesswork

A smart strategy isn’t just “gut feel.” Use data from:

• Maintenance logs to track repeat failures
• Vendor phase-out notices to anticipate obsolescence
• Tariff and import updates to understand cost and availability risks
• Supplier reliability to gauge whether “on-demand” sourcing is truly dependable

This information helps you focus inventory dollars on parts with the highest risk-reward balance.

Step 5: Review and Update Regularly

Your spare parts list isn’t static. Update it as:

• Equipment gets upgraded or phased out
• Vendors announce product end-of-life
• Lead times or tariffs shift due to supply chain changes

A review every 6–12 months ensures your strategy stays relevant.

Example: Prioritizing Drives

Take a plant running both legacy Allen-Bradley 1336 PLUS II drives and modern PowerFlex 525 units.

• The 1336 PLUS II is obsolete, with limited stock and long lead times → keep a spare or two on hand.
• The PowerFlex 525 is widely available and still in production → monitor failures, but stocking extras may not be essential.

This kind of part-by-part assessment avoids overstocking while still protecting your plant from downtime.

Spare Parts Prioritization Grid

Part	Criticality	Lead Time	Downtime Impact	Plan
Drive (legacy, line-critical)	High	8–12 weeks	High	Stock 1–2 units
PLC CPU (current)	High	3–5 days	High	Stock 1; repair as backup
HMI (current-gen)	Medium	2–3 days	Medium	Source on demand
Comms module (unique)	High	4–8 weeks	High	Stock 1; consider 2 for bottlenecks

Building Resilience Into Your Strategy

A smart spare parts strategy goes beyond the shelf:

• Partner with reliable suppliers who maintain large in-stock inventories
• Work with repair providers who can quickly turn around failed drives and PLCs
• Document emergency sourcing options so your team knows who to call when the unexpected happens

By combining stocking, sourcing, and repair, you can reduce downtime risk while keeping budgets under control.

Final Thoughts

The best spare parts strategy isn’t about having everything—it’s about having the right things. Prioritize based on criticality, lead time, and cost of downtime. Keep essential items in stock, leverage repair when possible, and build trusted supplier relationships to cover the rest.

At Industrial Automation Co., we specialize in helping manufacturers source critical automation parts fast—from legacy drives to modern PLCs. If you’re rethinking your spare parts strategy, our team can help you identify what’s essential and deliver it when you need it most.

Build Your Spare Parts Plan with Industrial Automation Co.