A workshop's spare parts store suffers from two opposite problems at the same time: parts sitting untouched for two years tying up cash, and parts needed daily running out so cars stand waiting.
The cause is the same for both: nobody knows exactly what is in the store, or what actually moves.
This guide covers spare parts management alone: how parts link to job cards, how to decide what is worth stocking, and how to stop the largest financial leak in the trade.
Leak one: parts fitted but never charged
This is the most common loss in car workshops, and the least visible in any report.
It rarely happens through bad intent. The technician needs the part to finish the job, takes it from stores and intends to record it shortly — then another car arrives and the day ends. The part was fitted, the car left, and the invoice went out short.
The fix is structural, not supervisory. Make it impossible to issue a part unless it is charged to a job card. Then nobody needs to remember, because the system does not permit the error in the first place.
The difference between the two approaches is fundamental: supervision depends on a busy person noticing; structure works on its own.
Leak two: dead stock
Parts that have not moved in a year are not a "reserve" — they are frozen cash and occupied space.
One report exposes them: parts sorted by date of last movement. Open it once a quarter and you will usually find a meaningful share of your store's value has not moved at all.
The decision then becomes clear: sell at a discount, return to the supplier if possible, or at minimum stop reordering.
What is worth stocking?
Not every part deserves a place in your store. The practical rule depends on two things: how often it is requested, and how long it takes to arrive from the supplier.
| Demand | Lead time | Decision |
|---|---|---|
| Frequent | Long | Stock with a clear minimum |
| Frequent | Short | Small quantity covering a few days |
| Rare | Short | Do not stock — order on demand |
| Rare | Long | Case-by-case decision |
The third row is what frees the largest amount of tied-up cash in most workshops.
Reorder level: the number that stops cars standing idle
Every frequently used part needs a minimum level at which the system alerts you. The calculation is simple: average daily consumption multiplied by lead time in days, plus a safety margin.
Without that level you operate in one of two ways, both costly: overstocking as insurance, or discovering a shortage when the car is already on the lift.
Customer-supplied and used parts
When a customer brings their own part, it must be recorded on the job card with its description and source — for two reasons: so it is not charged to them, and so it is documented that your warranty does not cover it.
This documentation ends a common dispute: a customer-supplied part fails, and the workshop is held responsible.
Frequently asked questions
How do I stop parts being fitted without billing?
By linking part issue to the job card in the system, so nothing leaves stores unless charged to a card. This structural fix makes the error impossible rather than relying on someone noticing.
How do I identify dead stock?
With a report sorting parts by date of last movement. Review it quarterly; you will usually find a meaningful share of store value has not moved in a year.
What is a reorder level and how is it calculated?
It is the balance at which the system alerts you to reorder. Calculate it as average daily consumption multiplied by supplier lead time in days, plus a safety margin.
Should I stock every part I use?
No. Rarely requested parts with short lead times are not worth stocking — order them on demand. That category specifically frees the most tied-up cash.
How do I handle a part the customer brings?
Record it on the job card with description and source without charging it, and document that your warranty does not cover it. This ends a common dispute if the part later fails.
Does the system link parts to suppliers?
In specialised systems yes, with purchase order tracking and a list of cars waiting for parts to arrive — the most common cause of delivery delays in workshops.
Conclusion
A spare parts store is not a warehouse; it is a running account. Every part in it is either money moving or money stopped.
Start with two reports: parts that have not moved in a year, and parts that ran out and held up a car last month. The first frees cash; the second prevents downtime.
This article is part of our guide to garage management software. To see how parts link to job cards in practice, review the auto repair workshop management system.