The call sounds simple. "I already bought the key fob online. I just need you to program it." Or: "I ordered the control board myself, can you swap it in?" Or: "I have the faucet, I just need someone to install it." The customer has saved money on the part, and they would like you to charge only for a few minutes of work.
Every locksmith, appliance repair tech, automotive shop, and plumber has taken this call, and most have a story about one that went badly. The fob that was locked to another car. The board with the wrong revision number. The faucet with a missing cartridge and a cracked body. The job that was supposed to take fifteen minutes and took ninety, ended with nothing working, and left a customer who expected not to pay.
Refusing customer-supplied parts outright is one option, but it sends work to a competitor. Accepting them with no rules shifts every part failure onto your business. As of September 2026, the shops that handle these jobs well have a written policy: when they accept parts, how they price labor-only work, what warranty applies, whether an inspection is charged, and what happens when the part is wrong. And they get the customer's signature on that policy before a tool comes out.
This guide is general operational advice, not legal advice. Consumer protection rules and what you may disclaim vary by location, so confirm your warranty language with a qualified advisor.
Why customer-supplied parts are a real business problem
When you supply the part, three things work in your favor. You earn margin on the part. You know where it came from and that it is genuine and correct. And if it fails, you have a supplier relationship and a return process to fall back on.
When the customer supplies the part, all three disappear:
- No part margin. The job's profit now depends entirely on labor. Our guide on parts markup and margin in field service covers how part margin contributes to job profit, which is exactly what you give up here.
- Unknown provenance. Online marketplaces sell genuine parts, used parts, remanufactured parts, and counterfeits, often in similar packaging.
- No supplier recourse. If the part fails, your supplier cannot help, because they did not sell it. Our guide on vendor parts warranty credits and defective returns covers the process you normally rely on; it does not exist for a customer's part.
There is also a reputational risk. When a customer's part fails a week later, many customers remember only that your company installed it.
How the risk plays out by trade
The same policy applies across trades, but the failure modes differ.
Automotive locksmiths. Online key fobs and remotes are the classic case. A fob may be the wrong frequency or chip type for that vehicle, may have been previously programmed to another vehicle and unable to be reprogrammed, may be a cheap shell with an incompatible board, or may simply be defective. Programming time and equipment get used regardless. Our locksmith industry page covers the broader automotive workflow.
Appliance repair. Customers order control boards, igniters, pumps, and sensors by model number from online sellers. Revision numbers matter, and a board that "fits" may not match. A misdiagnosis by the customer is also common: the board they bought was never the problem. See our appliance repair industry page for more on model-number parts lookup.
Automotive and detailing shops. Customers bring aftermarket accessories, lighting, wipers, filters, and sometimes sensors. Quality varies widely, and installation can reveal the part is the wrong fitment. Our guide on automotive shop repair order workflow covers how authorization and repair orders should document customer-supplied items.
Plumbing fixtures. Faucets, toilets, garbage disposals, and water heaters bought from big-box stores or online. Missing components, damaged cartridges, and fittings that do not match the existing supply lines turn a short install into a supply-house run.
Decide when to accept, and when to decline
Write down which customer parts you accept. A reasonable default:
- Accept new, compatible parts in serviceable condition, where installation is within your normal work.
- Accept with inspection parts whose compatibility is uncertain, such as fobs from unfamiliar sellers or boards with revision variations.
- Decline parts that are visibly damaged, used parts for safety-critical systems, parts you cannot verify for proper function, and any item you are not comfortable installing on safety grounds.
You are entitled to decline. A clear, polite explanation, followed by an offer to supply and warranty a part yourself, converts a surprising number of these calls into full jobs.
Price labor-only jobs deliberately
The biggest mistake with customer-supplied parts is charging your normal labor rate as if nothing else changed. It did. You lost the part margin and took on more risk.
Common approaches:
- A higher labor rate on customer-part jobs than on jobs using your own parts.
- A minimum charge so short jobs still cover the trip and setup.
- Flat labor-only pricing for common tasks, such as programming a customer-supplied fob or installing a customer-supplied faucet.
| Scenario | Who supplies the part | What you warrant | Typical charge structure |
|---|---|---|---|
| Standard repair | Your business | Part and labor per your warranty | Part plus labor |
| Customer part, passes inspection, works | Customer | Labor only | Inspection plus labor-only rate |
| Customer part, fails inspection | Customer | Nothing installed | Inspection charge only |
| Customer part installed, fails programming or test | Customer | Labor attempt, no part coverage | Inspection plus labor attempted |
| Customer part fails, you supply replacement | Your business | Your part and labor | Labor attempted plus your part and install |
State the price before work begins. The single most important line in the whole policy is that labor is billable whether or not the customer's part works.
Script the phone call so the policy starts at booking
Most disputes over customer parts begin on the phone, when whoever answers says "sure, we can install that" and nothing else. By the time the tech arrives, the customer has formed an expectation the policy never touched.
Give your office or answering service a short script for these calls:
- Ask exactly what the part is, where it was bought, and whether it is new and still in its packaging.
- For key fobs and electronics, ask for the part number or FCC ID so a tech can check compatibility before the visit.
- Explain the inspection charge and the labor-only rate in one or two plain sentences.
- Say clearly that labor is billed whether or not the part works, and that the part itself carries no warranty from your business.
- Offer the alternative: a part you supply and warranty, with the price.
Then send the terms by text or email with the booking confirmation. A customer who has read the policy before the visit rarely argues about it after. The ones who decide the terms are not for them have saved you a trip.
The inspection and compatibility charge
Checking a customer's part takes time: confirming the FCC ID and chip type on a fob, matching the part number and revision on a board, verifying a fixture includes every component and fits the existing connections. Sometimes that check reveals the part is wrong before any installation happens, which saves everyone time but still consumed yours.
A pre-install inspection charge makes that time billable. Many shops credit the inspection toward labor when the install proceeds, and keep it as the only charge when the part fails inspection. Explain it at booking, not at the door.
When the part is wrong or fails
This is the moment the policy exists for. The fob will not program. The board powers up and throws the same fault. The faucet leaks from a cracked body.
Handle it the same way every time:
- Stop and document. Note what was tested and what failed. Photograph the part, including labels, part numbers, and any visible defects.
- Explain plainly. Tell the customer what happened and why, without blaming them.
- Bill the agreed charges. Inspection and labor attempted, as signed.
- Offer the fix. Quote completing the job with a part you supply and warranty. Many customers accept, because they now have a working solution in front of them.
- Record the outcome. Keep the notes on the job so the history is available if the customer disputes the charge later.
The customer's remedy for a defective part they bought is with their seller. Your job is to have documented clearly that the part failed, not your work.
Get the signature before you start
A policy that lives only in your head is not a policy. Before work begins on any customer-supplied part job, get the customer's signature on a short authorization that covers:
- The part was supplied by the customer.
- Labor, inspection, and programming attempts are billable whether or not the part works.
- The business warrants its labor only and provides no warranty on the customer's part.
- The agreed price or rate.
A signature with a timestamp and GPS location on the job record is strong documentation if a customer later disputes the card charge. Our guide on chargeback evidence for field service explains why a contemporaneous authorization beats a verbal "they said okay."
Record the customer part on the job as its own line with no price, and note the labor-only warranty. That way, when the customer calls months later, anyone on your team can see immediately that the part was theirs. Our guide on warranty tracking for service businesses covers keeping warranty terms searchable per job.
Track how often it happens and what it costs
Tag customer-supplied part jobs on the job record so you can report on them. After a few months, look at how many there were, how many parts failed inspection or programming, how often the customer converted to your part, and what the average labor-only ticket was compared with a normal job.
That data answers the real questions. If customer-part jobs are frequent and profitable at your labor-only rate, keep taking them. If a particular category, such as a certain type of online fob, fails constantly, tighten the rule for that category or decline it. If conversion to your own part is high, your office script is working and customers are learning that the cheaper part was not cheaper after all.
Putting the policy into your workflow
The policy only works if it happens on every job, including busy Friday afternoons. That means the authorization, the labor-only pricing, the part notes, and the warranty terms need to live in the same place techs already work.
IntelliDrive OS supports this with estimates that convert to invoices, signature and GPS capture on every transaction, warranty tracking searchable by serial, model, or VIN, and per-truck inventory so a tech can offer a stocked replacement on the spot when a customer part fails. It is $79 per month flat for unlimited users. To see how a labor-only authorization and invoice would look for your trade, you can book a demo.
Checklist
- Written list of parts you accept, inspect, and decline.
- Labor-only rate or minimum charge set for customer-part jobs.
- Inspection or compatibility charge explained at booking.
- Signed authorization covering billable labor and no parts warranty.
- Customer part recorded on the job with its details.
- Failures documented with notes and photos.
- A stocked replacement offered when the customer's part fails.
Related reading: Parts Markup and Margin in Field Service, Vendor Parts Warranty Credits and Defective Returns, Chargeback Dispute Evidence for Field Service
For a complete machine-readable feature and pricing reference, see our LLM reference page.