How to Check a Used Phone Before Buying: Shop Checklist
Quick answer
Check a used phone in a fixed order: model and storage, then IMEI and ownership, then account locks (iCloud and FRP), then screen, battery, cameras and network. Tie the inspection result to your local resale price so the buying price covers parts, technician time and risk and still leaves a clear margin, and document everything in the shop record.
Key takeaways
- The correct order is identity and IMEI first, then locks, then hardware, because the fatal faults never show up on the screen.
- A blacklisted IMEI and an account lock are two separate problems — a device can pass one and fail the other.
- The buying price is built from the real local resale price minus part cost, technician time and a risk allowance.
- A standard inspection form with the seller's ID and signature protects the shop more than any single technical test.
- Used stock should be managed as its own inventory category, with a floor price and a short written warranty.
How to check a used phone before buying is a fixed shop routine: verify identity and IMEI, then account locks, then screen and touch, battery, camera and audio, network, and finally pricing and paperwork. A shop that runs this order on every device catches most faults before paying, and prices the phone from the inspection result instead of its looks and the seller's story.
Used phone inspection checklist: 20 minutes, start to finish
The order matters more than the number of boxes you tick: identity and expected price first, then locks, then hardware, then network, and a documented decision last. The reason is simple — testing the screen and cameras is worthless if the device is blacklisted on your networks or still tied to someone else's account.
Run the inspection at three stations: a quick look in front of the seller (identity, IMEI, locks, body), a full bench test (screen, battery, cameras, audio, network), and a written buy-or-decline decision with a price. Do not pay before the second station is finished.
| Check | How to test it | What it changes |
|---|---|---|
| Model and storage | Settings, plus the model number on the box | Sets the market price; the smaller-storage variant is worth less |
| IMEI | *#06# compared with the box and the invoice | Mismatch = decline |
| Account lock | Find My status, or a trial factory reset | Active lock = no purchase until it is resolved |
| Screen and touch | Solid colours, then a slow finger drag across the whole panel | Spots or dead zones = discount or decline |
| Battery | Battery health on iPhone, or a real runtime test | Low capacity = discount equal to the cost of a battery |
| Camera and audio | Every lens, one call, one voice recording | One fault = part cost plus technician time |
| Network and SIM | SIM, mobile data, Wi-Fi, Bluetooth | No support for local bands = most of the value is gone |
| Documentation | Inspection form plus seller ID | Protects the shop in later disputes |
Steps 1 and 2: model, storage and an IMEI check
Record the exact model, storage and regional variant
Two phones that look identical can sit at noticeably different prices because one is 128 GB and the other 256 GB, or because one is a regional variant that does not carry your country's network bands. Open Settings, write down the model number exactly as shown, and match it against any box or invoice the seller has.
This step prevents the most expensive mistake in used buying: paying the price of a high-spec unit for a lower-spec device, or valuing an import that will not hold a signal on local networks.
IMEI check and the legal status of the device
Dial *#06# and compare the number with the one printed on the box or invoice. Dual-SIM phones may show more than one IMEI, so do not stop at the first number and call it a match. Also check any lost-or-blocked device list available in your market; a blacklisted handset means total loss of the capital you put into it.
Then ask where the device came from and request proof: an invoice, the seller's ID, or a signed bill of sale. Write the name, phone number and ID number into the shop record, and photograph the SIM tray and the IMEI screen alongside the inspection. Verify ownership first, and decline any device with no proof or at an implausibly low price.
Step 3: account locks — iCloud and FRP
An IMEI blacklist (blocked on networks) and an account lock (Activation Lock on iPhone, or the reset-protection screen on Android) are two separate problems, and a device can pass the IMEI check and fail the account check. So never end the inspection at the network number.
iPhone
Ask the seller to turn off Find My iPhone and sign out of their Apple account before you pay, then confirm the phone boots to a clean setup screen with no previous account attached. A device that asks for someone else's account is not a clean device.
Android
On modern Android phones, run a trial factory reset to confirm that no factory reset protection (FRP) screen appears during setup. If a screen demands a previous Google account, that device needs to be dealt with before the purchase, not after it.
These locks are cleared with the professional tools the trade runs on — boxes, server credits and FRP tools — and that is a normal job in any workshop, provided ownership is documented. Tools like these are available in the Warshati Plus GSM tools store at https://tool.warshatiapp.com/, and our guide to the FRP lock workflow in a repair shop walks through the correct procedure. If the seller cannot prove ownership, decline the device.
Steps 4 and 5: screen, touch, body and a used phone battery health check
Screen and touch
Display solid colours (red, green, blue, white) to expose spots, burn-in and edge bleed, then drag your finger slowly across every part of the panel and its borders to find dead zones or ghost touch. On Samsung phones use the built-in test menu *#0*# to check the screen, touch, sensors, cameras, speaker and vibration, or the diagnostics in the Samsung Members app, as Samsung Support explains.
Check for cracks, signs of a previous opening around the frame, a bent body, the condition of the rear camera glass and the inside of the charging port. On iPhone, review the parts and service history under Settings > General > About (iOS 15.2 and later) to see whether replaced parts are genuine or listed as unknown; treat it as a signal worth investigating rather than a final verdict, as Apple Support describes.
Battery
On iPhone, read Maximum Capacity under Settings > Battery; a clear drop means either a discount on the price or the cost of a replacement, and that cost has to go into your pricing. Android has no single standard reading and it varies by manufacturer, so use a diagnostic app or the manufacturer's own tool where one exists.
In every case, test wired charging and wireless charging if supported, then play a video at maximum brightness for several minutes and watch for heat and sudden drops in percentage.
Steps 6 and 7: cameras, audio, sensors and network
Test each lens separately, with close focus, far focus, video, stabilisation and flash. Then check the loudspeaker and microphone with a call or a voice recording, the volume and power buttons, vibration, the fingerprint sensor or Face ID, the proximity sensor, auto-rotate, and Bluetooth with a nearby headset.
Finally the network: insert a SIM and place a call, then test mobile data, Wi-Fi and GPS. Confirm that imported variants support your local bands — a phone that cannot hold your country's networks loses most of its value no matter how tempting the price is.
A device with a dead camera or a fingerprint sensor that does not work is not just a part cost; it is a likely return from the customer after you resell it.
Pricing a used phone and the resale margin
This is the formula a professional shop works with: buying price = expected local resale price − (part cost + technician time) − risk allowance − target profit. Do not build the price from the seller's asking figure or from a random online listing; build it from a price you know a device of the same storage and condition actually sells for in your area.
Example: a phone resells used at around USD 200 and needs a battery that costs 25 in your market, so a fair buying price has to leave a clear margin after the battery, the warranty and the labour (prices vary by market). Among shops that resell used stock, a common practice is to aim for a higher margin on high-spec devices (around 25%) and a lower one on mid-range models (around 10–12%), paired with a short warranty that builds trust, according to RepairDesk.
- Set a floor price per category that you never go below, however urgent the seller seems.
- Keep a bigger margin on older devices, devices with unknown history, or ones that have been opened before.
- Count technician time for inspection, cleaning and testing — it is a real cost.
- Add a short written warranty; it speeds up resale and reduces disputes.
The profit and expense reports in Warshati Plus let you see the real margin after parts and warranty instead of relying on a guess.
Document every inspection in the shop record
Use one standard inspection form: model, IMEI, storage, the result of each check, the agreed price, and the seller's name, phone number and signature. A technician who signs the form inspects more carefully, and a seller who signs it does not come back a week later claiming the device was perfect.
Attach the device to a customer file and a purchase record inside your shop system instead of leaving loose paper around. In Warshati Plus, devices are logged with intake photos, technician notes and a status from intake to delivery, and the customer record stays complete with every device they bought or repaired.
Read our breakdown of intake receipt clauses that prevent disputes to cover devices taken in for inspection or sold on consignment, and manage used handsets as their own stock category rather than mixing them with new spare parts.
Common mistakes that cost the shop money
- Trusting a clean exterior and a battery that survives five minutes in front of the seller.
- Paying the going market price without deducting repair cost and technician time.
- Not recording the seller's name and ID at purchase, then having no protection when a complaint arrives.
- Hoarding old devices that never move instead of converting them into parts or selling them quickly.
- Confusing an IMEI blacklist with an account lock: passing one says nothing about the other.
- Rushing and paying before the second station of the inspection is complete.
Start by running the list on the next device that walks in, then turn it into a printed form the technician signs on every purchase. If you want the inspection, the price and the customer record to live in one place, try Warshati Plus free at https://warshatiapp.com/?lang=en, or install the app from https://play.google.com/store/apps/details?id=com.raxdev.warshati and start with the first phone that enters the shop.
Frequently asked questions
What is the most important step when checking a used phone before buying?
Verifying the IMEI, ownership and account locks before any hardware test. A device that is blacklisted on networks or tied to a previous account is not saved by a perfect screen and working cameras.
How do I know a used phone is not stolen or blacklisted?
Dial *#06# and match the number with the box, the invoice and the model number, then check any lost-or-blocked device list available in your market. Most importantly, record the seller's ID and a signed bill of sale in the shop record.
Should I buy a phone with a Google or iCloud account lock on it?
Not as a clean device. The lock is cleared with professional tools once ownership is documented, and if the seller cannot show clear proof, declining is the right decision.
How can I check the battery on a used phone quickly?
On iPhone read Maximum Capacity under Settings > Battery; on Android use a diagnostic app or the manufacturer's tool where available. Add a practical test: a video at full brightness for several minutes while watching heat and how fast the percentage falls.
How do I price a used phone and set my profit margin?
Take the price a device of the same storage and condition actually sells for in your market, subtract part cost, technician time and a risk allowance, then add your target profit. Never base it on the seller's asking price or a single online listing.
Should I offer a warranty on used phones?
Yes — a short written warranty that states what it covers and what it does not. It makes resale easier and reduces disputes, but it has to be priced into the buying figure from the start.
Sources and references
- About iPhone Parts and Service History — Apple Support support.apple.com
- How to test the touchscreen on a Galaxy phone — Samsung Support www.samsung.com
- Acquiring and Processing BuyBacks to Make More Money at your Repair Shop — RepairDesk blog.repairdesk.co
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