A customer comes to the service with a device in hand and asks if it is under warranty. The answer depends on a single piece of information: when and to whom did you sell this device?
In a business without serial number tracking, this question is searched for in the invoice archive. If the customer has lost their receipt, there is no answer.
In this article, we explained when serial number tracking is needed, how it is set up, and how it connects to the service process.
Table of Contents
When is it necessary?
Serial number tracking is not required for every product. It comes into play when one of three conditions is met.
Warranty commitment. If the product has a warranty for a specific period, the start of that period depends on the date of sale. This connection is established via the serial number.
Service requirement. If the product undergoes maintenance or repair, past operations must be kept tied to the device. When the same device malfunctions for the third time, this information changes the decision.
High unit value. For high-value products, item-level tracking prevents loss and confusion.
Electronics, home appliances, machinery, medical devices, and business equipment are typical examples.
Difference from lot tracking
A lot tracks a group, while a serial number tracks a single product. In lot tracking, you say "we sold one hundred units from this batch"; in serial tracking, you say "this device belongs to that customer."
Both can also be used together. A device can have both a production batch and a unique serial number; the batch is used for quality issues, and the serial number is used for warranty questions.
We detailed the lot structure in the batch and lot tracking article.
In terms of operational cost, serial tracking is heavier: each unit is recorded separately. Therefore, it should not be enabled unless truly necessary.
Setting up serial tracking
Tracking is enabled at the product card level. For cards marked as serial-tracked, every movement requires a serial number.
Numbers generally come from the manufacturer and are found as barcodes on the device. In this case, scanning is sufficient; manual entry is not required.
In cases where the manufacturer does not provide numbers, you can generate your own numbering scheme. This is common in heavy machinery and custom-produced equipment.
Barcode scanning discipline is decisive here; you can check out the barcode management article.
Flow from receipt to sale
During goods receipt, the serial number of each device is scanned and entered into stock. When this step is skipped, all subsequent links break.
In intra-warehouse transfers, which device went to which warehouse is recorded; see the transfer slip article.
During a sale, the serial number is linked to the invoice line. Thus, the question "to whom was this device sold" is answered with a single query.
During stock counting, it is not the quantity that is verified, but which specific serial numbers are present. This catches missing devices early; you can refer to the warehouse stock count article.
Warranty and service connection
The true value of serial number tracking emerges after the sale. When the device arrives at the service, the number is queried, and the sales date, customer, and past operations become visible.
This enables warranty decisions to be made within seconds. There is no need to ask the customer for documentation.
Service history is also kept tied to the device. Recurring malfunctions can signal a product- or supplier-related issue, which we covered in the warranty and spare parts tracking article.
The same logic applies to equipment you use yourself; in asset management, devices are tracked along with custody assignments. The inventory module covers this side.
Operational cost
Serial tracking is not free; every movement requires an additional scanning step. This burden is felt on high-volume products.
Therefore, make the decision on a product basis. In the same business, some cards can be serial-tracked while others are not.
The way to reduce the load is to make scanning mandatory yet fast. A workflow with bulk scanning support registers ten devices in seconds.
Serial number records are kept as card sub-definitions in the stock module and linked to the sales document.
Impact on customer experience
The most visible benefit of serial number tracking appears on the customer side. Asking a customer who has lost their receipt to "tell us the serial number of the device" resolves the issue instantly.
This eliminates most of the tensions experienced at the service point. The customer does not have to search for documents, and the staff does not wait to make a decision.
The second benefit is consistency in warranty decisions. Different staff members are prevented from making different decisions; whatever the record says is applied.
The third is proactive communication. When a systematic issue is detected in a product, customers who purchased that batch can be reached out to in advance. This means offering a solution before a complaint arises.
Conducting customer communications with records completes this process; you can check out the service request and SLA tracking article.
Transitioning existing stock
It is possible to enable serial tracking later, but numbers must be entered for existing stock. This is an undertaking that requires planning.
The most appropriate time is the inventory count period. Every product will be handled anyway; scanning the serial number adds no extra burden.
An alternative approach is a phased transition: existing stock remains untracked, while new receipts are processed with serial tracking. Over time, as old stock is depleted, the transition is completed.
The disadvantage of this method is that two different conditions exist for the same product during the transition period. The team needs to know this and provide accurate information to the customer.
You should also choose which products to start the transition with; starting with items carrying the highest warranty load yields the fastest benefit. We covered count planning in the warehouse stock count article.
Frequently asked questions
Should the serial number be shown on the invoice?
It is not mandatory, but it facilitates warranty processes. It can be added through document design; check out the document design article.
Can a returned device be resold?
Yes; the serial number re-enters stock and its history is preserved. We covered the return workflow in the return management article.
Can serial tracking be enabled later?
It can be enabled, but numbers must be entered for existing stock. Inventory count day is ideal for this task.
How is a service request linked to the device?
The serial number is selected while opening a request; you can look at the service request and SLA article.
Serial number tracking is a structure that incurs a cost of a few seconds at the time of sale and saves hours afterward. The decision comes down to understanding your product's warranty and service load.
There is a simple test for this decision: how many minutes does it take to give an answer when a customer comes in with their product and asks about the warranty? If the duration is longer than a few minutes, serial tracking will benefit your business.
Start implementation with the product group that has the highest warranty load. Enabling it across the entire catalog all at once will unnecessarily slow down warehouse operations.
Measure the gain at the end of the first quarter: how much did the warranty query duration shorten, how many disputes were resolved with records? These data points make the decision to expand the scope easier.
By consulting with the EQLEM team, you can plan your serial tracking and service connection.