What to check when buying a used phone: a step-by-step checklist
From IMEI registration and account locks to battery health and the screen: everything to check before you buy a used phone.
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Chosen carefully, a used phone can save you a good deal of money and still serve you well for a long time. But even a phone that looks spotless can hide a registration problem, an account lock or a tired battery. Spending a few minutes on the checklist below before you pay can spare you a lot of regret later.
1. Check the IMEI registration
The IMEI is a unique 15-digit number that identifies every phone. In Turkey, a phone can only be used long term with a Turkish SIM if its IMEI is registered with the national telecoms regulator, the Information and Communication Technologies Authority (BTK). Phones sold through official channels in Turkey come registered. A phone brought in from abroad that was never registered (registration involves paying a fee) will be cut off from Turkish networks after a while, and one reported lost or stolen can't be used on them at all.
Dial *#06# on the phone's keypad and the IMEI appears on screen. Dual-SIM phones show two numbers.
Compare them with the label on the box and with the “About” section in the phone's settings. If the numbers don't match, walk away.
Check the number with the IMEI Sorgulama (IMEI check) service on e-Devlet, Turkey's official e-government portal. It should show the phone as registered. If it says unregistered, lost or stolen, don't buy it.
Putting your own SIM in and making a quick call is a good test, but it isn't enough on its own: an unregistered phone may work for a while and then be cut off. Always do the IMEI check.
2. The iCloud or Google lock must be removed
If the previous owner's account is still on the phone, it will ask for that account's password after a reset. On an iPhone this is called Activation Lock; on Android it's Factory Reset Protection (FRP). In practice only the previous owner can remove it, and you won't be able to use a locked phone.
Ask the seller to sign out of their Apple or Google account and factory reset the phone in front of you.
After the reset, the phone should start with the setup screen, as if it were new, and shouldn't ask for anyone else's account during setup.
On an iPhone, if someone else's name appears at the top of Settings, their account is still on the phone.
In short: never buy a phone that fails the IMEI check or still has an account lock, however tempting the price.
3. Check the battery health
On an iPhone, Settings > Battery shows battery health as a percentage. The lower it is, the faster the charge runs out, and once it drops below 80%, a replacement is usually worth considering. On Android this information isn't in the same place for every brand: some models show it in Settings, others in the manufacturer's own support app.
Beyond the figure, use the phone for a while. If it warms up quickly or the charge level suddenly drops, the battery may be worn. If the battery is weak, factor that into the price; a battery replacement often makes the phone comfortable to use again.
4. Test the screen and touch
Open a plain white, a plain black and a single-colour image. Look for dots that never light up or always stay one colour (dead pixels), yellow patches and colour tints.
On OLED screens, look for faint shadows on a grey or white background. Known as burn-in, they're left by showing the same image for a long time, and they don't fade away.
Drag an app icon with your finger right into all four corners of the screen. No area should stick or ignore your touch.
Turn the brightness from minimum to maximum, and tilt the screen towards the light to spot scratches and cracks.
5. Cameras, Face ID or fingerprint, sound and buttons
Take photos and a short video with sound on every front and rear camera, including the wide-angle and zoom lenses if it has them. Focus and flash should work, with no spots or shaking in the picture.
Try registering a new face for Face ID or a new fingerprint.
Make a call and test the earpiece, the loudspeaker and the microphone. Record a short voice memo and play it back.
Plug in the charging cable: the phone should charge and the cable shouldn't sit loosely.
Try the power and volume buttons, the silent switch if there is one, and the vibration. Turn on Wi-Fi, Bluetooth and mobile data as well.
6. Signs of previous repair or water damage
Look for gaps between the screen and the frame, excess glue, scratched or missing screws, dust under the glass and condensation inside the camera lenses.
Some models have a small indicator inside the SIM tray slot that changes colour after contact with liquid.
On iPhones, if Settings > General > About shows a “Parts and Service History” section, you can see there which parts have been replaced. “Unknown Part” can mean a non-genuine part was used.
A repaired phone isn't automatically a bad buy. What matters is that the seller tells you openly and the price reflects it.
7. Box, invoice and warranty
The IMEI and serial number on the box should match the phone.
The invoice shows where and when the phone was bought, and you'll usually need it to make a warranty claim.
Many brands let you check on their official website whether the warranty is still valid, using the serial number or IMEI.
If you're buying from a private seller, ask for a simple bill of sale showing the seller's name and phone number, the IMEI and the price.
If the price looks too good to be true
A price well below the going rate is often a sign of a problem: an unregistered device, an account lock, a hidden fault or even a stolen phone. Be especially careful if:
the seller is rushing you or won't let you test the phone;
there's no box, invoice or IMEI information, or the details don't match;
you're asked for a deposit before you've seen the phone.
Buy from somewhere you trust
The safest option is to buy from a seller with a fixed address who answers your questions openly and lets you test the phone. At Işıltı İletişim in Kahramanmaraş, every used and refurbished phone we sell has its condition and battery health stated on its listing. If anything is unclear, just ask us before you buy.