When buying a used smartphone, check five things above all: battery health, screen and cameras, the IMEI against the receipt, whether Activation Lock or the Google account lock has been removed, and whether the phone is network locked. Who you buy from matters just as much, because it determines your legal rights and whether you can return the phone. This checklist is mainly for buying from a private seller.
What should you check before buying?
With a private sale, every check is down to you. A refurbished phone, by contrast, has already been tested and, where needed, repaired by a retailer; our guide refurbished vs used explains the difference.
If you buy from a business seller in the EU, the legal guarantee of conformity applies, and online you usually also have a 14-day right of withdrawal. Private sellers can exclude the legal guarantee, and there is normally no right of withdrawal. This is general information, not legal advice.
On eBay or Vinted, the listing shows whether a business or a private individual is selling and which return terms apply. Always pay through the platform, never by bank transfer outside it, or its protection will usually not apply.
How do you check the battery, screen, cameras and buttons?
Ideally, bring a charging cable and a second SIM card.
- Battery: on an iPhone, you'll find the figure under Settings > Battery. According to Apple, an iPhone battery is designed to retain up to 80% of its original capacity after 500 complete charge cycles, or after 1,000 cycles for iPhone 15 models and later. Many Samsung devices offer a battery diagnostic in the Samsung Members app; our guide to checking battery health explains each step.
- Screen: at maximum brightness, open a fully white, black, red, green and blue image in turn to reveal dead pixels and burn-in. To test touch, slowly drag an app icon across the whole screen.
- Cameras and audio: take a photo and a short video with every camera. Record and play back a voice message to test the microphone and speaker in one go.
- Buttons and ports: press every button, check that the phone charges, and test Face ID or the fingerprint sensor, Wi-Fi, Bluetooth and GPS.
How do you check the IMEI and account lock?
Open the Phone app and dial *#06#: the 15-digit IMEI must match the receipt and the original box, otherwise the paperwork may belong to another device.
The account lock is the most important check, because the phone can't be set up without the previous owner's login details. On an iPhone, Activation Lock links the device to the owner's Apple Account while Find My is turned on. On Android, the Google account lock (FRP) asks for the old Google account's login details after a reset, and on Samsung devices the same applies to the Samsung account. Ideally, the seller signs out in front of you and resets the phone. If a lock message still appears during setup, don't buy it.
How do you spot a network lock or water damage?
Insert a SIM card from another network, make a short call and use mobile data. On an iPhone, “Carrier Lock” under Settings > General > About shows the status: “No SIM restrictions” means the phone is unlocked. Signs of water damage include condensation under the camera glass or display, corrosion in the charging port or SIM tray and, on many iPhones, a liquid contact indicator in the SIM tray slot that has turned red.
Checklist: every check at a glance
| Stage | Check | What to look for | OK? |
|---|---|---|---|
| Before buying | Seller | Business seller (legal guarantee) or private sale? | |
| Before buying | Receipt | Original receipt with IMEI | |
| Testing | Battery health | At around 80% or less, plan a replacement | |
| Testing | Screen, cameras, buttons | No dead pixels, touch works everywhere | |
| Testing | IMEI and account lock | *#06# matches, Find My off, Google account removed | |
| Testing | Network lock | SIM card from another network works | |
| After buying | Setup | Own account, software updates installed | |
| After buying | Everyday test | Use it a lot within the return period |
If the phone links to your Apple Account or Google account without an error message after you buy it, no lock is active. Report any problem within the return period, ideally in writing with photos.
Buying a used smartphone from tested before
With us, these checks are already done for you: every smartphone is tested before sale (screen, battery, buttons, cameras, ports and connectivity) and reset to factory settings with the previous owner's accounts removed. The listing on eBay or Vinted shows an honest condition grade with real photos, and you buy with the platform's protection under its terms; our quality page explains how we test. Browse our tested used smartphones.
