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Checklist: test a used Android phone before you buy it

A step-by-step checklist to check a used Android phone before buying: account locks, the IMEI, the screen and buttons, hardware tests, and what to do once it is yours.

Updated 15 September 20264 min read

A trader and a boy at an outdoor stall of second-hand phones and parts

Short answer

Before you meet the seller

  • Ask for the IMEI. On most phones you can see it by dialling *#06# or in Settings › About phone. Check it with your mobile carrier, or with an official IMEI check service in your country if one exists, to see whether the phone is reported lost or stolen.
  • Ask whether the Google Account has been removed. Android has factory reset protection. Google states that after a reset, a protected phone asks for the previous screen lock or Google Account password. If you cannot provide it, “you won’t be able to use the device at all after factory reset.” [1] The seller turns this off by removing their Google Account from the phone. [1]
  • Meet somewhere with Wi-Fi and a charger, so you can test the phone properly.

Physical checks

  • Screen. Open a plain white image and a plain black image at full screen. Look for marks, lines, dead pixels or burn-in. Drag an app icon slowly to every corner to check that touch works everywhere.
  • Body. Look for cracks, a bent frame, a swollen back or gaps around the screen. A swollen back can mean a battery problem.
  • Ports. Plug in a charger and check that it charges. If the phone has a headphone socket, try headphones.
  • Buttons. Press power, volume up and volume down. Each should click and respond.
  • SIM. Put your SIM card in, make a short call and check mobile data.
  • Cameras. Take a photo and a short video with each camera, then zoom in to check focus.
  • Account lock. Open Settings › Accounts (or Passwords & accounts). There should be no Google Account from the previous owner.

Hardware tests with Applore

Install Applore from Google Play on the phone you are checking. It works on Android 8.0 and up.

  1. Open Applore. On the Home tab, scroll to Device Information and tap Hardware Test.
  2. Run each of the ten tests: Flashlight, Loudspeaker, Ear Speaker, Ear Proximity, Light Sensor, Vibration, Bluetooth, Fingerprint, Volume Up and Volume Down.
  3. Tap Pass or Fail after each one. Take a screenshot of the grid when you finish, because the badges can reset.
  4. Go back and tap Device Information. Check that the model, Android version, storage size and cameras match what the seller advertised. Look at the Battery tab for the battery details Android reports.

Applore does not test the screen, so do the screen checks above by eye. Step-by-step details are in how to test your phone’s speakers, sensors and buttons.

After you buy

  1. Factory reset the phone. On most phones: Settings › System › Reset options › Erase all data (factory reset). Menu names vary by manufacturer. A factory reset erases everything on the phone and cannot be undone, so back up anything of yours first.
  2. Set it up with your own Google Account, and set a screen lock.
  3. Run Safety Check in Applore. Safety Check is a guided review of settings someone could have changed. It covers accessibility services, device admin apps, notification access, screen lock, and developer options and USB debugging. Applore opens the right settings screen for each item.
  4. Look at Needs your review. Needs your review checks installed apps against a reviewed list of known stalkerware, based on Echap’s public indicators, and flags apps that need your review. [2] This is useful if you skipped the reset or the phone came with apps installed.

Common problems

The phone asks for the previous owner’s account after a reset

This is factory reset protection. Only the previous owner’s Google Account password or screen lock will unlock it. [1] Contact the seller. Do not buy a phone that is still locked to someone else’s account.

A hardware test fails

Try once more without a case or screen protector, and with Bluetooth permission allowed. If the test still fails, treat it as a fault and factor it into your decision.

Device Information shows different storage from the advert

Storage shown in Settings is always less than the advertised size, because the system takes up space. A large difference, such as half the size, is worth asking about.

Applore flags an app after the reset

Some phones come with the maker’s or carrier’s apps. Read what Applore says about the app before you act. If you installed it yourself, you can mark it as trusted.

What stays private

Hardware Test results are stored on the phone. The stalkerware check and Safety Check run on the phone, and their findings stay there. The list of installed apps is not sent to analytics. If you install Applore only to test a phone before buying, uninstall it afterwards or remove it with the factory reset.

Next steps

Questions

Should I factory reset a used phone?

Yes. A factory reset removes the previous owner's apps, accounts and settings, including anything they may have installed to monitor the phone. Do it before you add your own accounts. A reset erases everything on the phone and cannot be undone. Make sure the seller has removed their Google Account first, or you may not be able to set the phone up.

What does Applore's Hardware Test cover?

Ten manual tests: flashlight, loudspeaker, earpiece, ear proximity sensor, light sensor, vibration, Bluetooth, fingerprint sensor, volume up and volume down. You tap Pass or Fail for each. There is no screen or touch test, so check the display by eye. It is free and runs on the phone.

Sources

  1. Help prevent others from using your device without permission, Android Help. Checked 2026-09-15.
  2. Stalkerware indicators, Echap (CC BY 4.0). Checked 2026-09-15.

Get Applore on Google Play

Manage apps and files, lock private apps, and check for known stalkerware.

Free on Google Play · Android 8.0 and up