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How to check used AirPods and headphones before you buy

Updated September 27, 2026

Used wireless earbuds and headphones such as AirPods, Galaxy Buds and Sony WF/WH sell in huge numbers, but they are also the most counterfeited gadgets around. Even genuine ones have a part that wears out early and sellers rarely mention: the battery in each earbud. This guide gets you through a check in about 15 minutes.

Tip: bring your own phone to pair them, and open soimay.com to play test sounds to each ear.

1. Genuine or fake

Fake AirPods now show the same pairing pop-up and animation as real ones, so don't rely on that. Check instead:

  • Serial number: printed inside the case lid. Pair with an iPhone, go to Settings › [AirPods name] and scroll to the bottom for the Serial Number and firmware version. The two serials must match, and entering it on Apple's coverage check page must show the right model.
  • Real AirPods have the full set of settings: Find My, noise control and Spatial Audio (on models that support it). Fakes usually lack them, or the switches do nothing.
  • Samsung Galaxy Buds: pair with the Galaxy Wearable app; Sony: the Sony | Sound Connect (Headphones Connect) app. Fakes usually can't connect to the brand's app or update their firmware.
  • An unusually low price, blurry box printing, typos and a loose case hinge are all red flags.

2. Mismatched earbuds or case

Many used sets have had a single earbud or the case replaced (bought separately after one was lost). That's not necessarily bad, but the price should reflect it. On AirPods, Settings › [AirPods name] can show separate serials for the case and each earbud; a bud from another generation or a non-genuine part will show an error or refuse to pair.

3. Removed from the seller's account?

Recent AirPods and Galaxy Buds are tied to the previous owner's Find My or SmartThings Find. If they haven't been removed, your iPhone may say the AirPods are "linked to another Apple ID" and the old owner can still see where they are.

  • Ask the seller to remove them from their devices (Forget This Device, then remove them in Find My).
  • Then reset them: for AirPods, put both buds in the case, open the lid and hold the button on the back of the case for about 15 seconds until the light flashes amber, then white (AirPods 4 have no button: follow Apple's reset steps, which use taps on the front of the case).

4. Sound in each ear

Pair them with your phone, wear both, and open the headphone test (choose Headphones as the device type on the soimay.com home page to go through the mic test and checklist too):

  • Play left, then right: each sound must come from the right side, with neither side clearly quieter.
  • Play the in phase and out of phase noises: in phase should sound focused in the middle of your head. If it's the other way round, one side has reversed polarity, common after a cable repair.
  • Turn the volume down low, then sweep from low to high frequencies and listen for crackling, buzzing or rattling anywhere in the range. Earbuds that got wet or have clogged drivers often distort in the bass.
Headphone test: left, right, phase, distortionTest headphones, AirPods or Galaxy Buds in your browser: play left and right separately, check polarity, sweep 20 Hz–20 kHz, test the mic and each earbud's battery.

A clogged speaker mesh makes sound quiet and muffled: look for earwax or dust packed into the mesh.

5. Noise cancelling and transparency

Go somewhere noisy (a fan, traffic) and turn on active noise cancellation (ANC): the background noise should drop clearly. Switch to Transparency: you should hear your surroundings naturally. Weak noise cancelling or a whistling, squealing sound when it's on usually means a dirty or faulty outer microphone.

6. Microphones

Call someone with the earbuds in and ask how clearly they hear you. Or record with the mic test while the earbuds are connected and play it back. Try each side: take one earbud out and the mic should switch to the other.

7. Battery in each earbud (the big one)

Earbud batteries are tiny, so they wear out fast, often within 2–3 years, and can't be swapped like a phone battery.

  • Charge both buds to full, then play music for 30–60 minutes at a normal volume.
  • Check each bud's level: on iPhone add the Batteries widget to the home screen; on Android use the brand's app.
  • Both sides should drop by about the same amount. One side draining much faster (more than 10–15% apart) means its battery is worn. Healthy earbuds usually lose only about 10–20% per hour, depending on the model.
  • Put them back in the case: each bud should show as charging. Leave the case unplugged overnight: a big drop means the case battery is weak.

8. Connection and sensors

  • Walk 5–10 m away from the phone, through a wall: the sound shouldn't keep cutting out.
  • In-ear detection: take one bud out and the music should pause; put it back and it resumes (on models that have it).
  • Controls: squeeze the stem (AirPods Pro) or tap (Galaxy Buds, Sony) to pause, skip tracks and switch noise modes.

9. Case and hygiene

  • The lid should snap shut with a firm magnet, not flop, and the buds should click into place.
  • Plug in the charging cable and wiggle it gently: the charging light shouldn't flicker. If the case supports wireless charging, try it on a pad.
  • Look at the charging contacts in the case and on the buds: no rust or black marks.
  • Earbuds go in your ears: fit new silicone tips and clean the mesh after you buy.

When you're done

On soimay.com, the Results page lets you save a PDF or create a report link and QR code with the headphones' name, as a record of how they tested when you bought them. The hands-on checks (genuine, battery, case, noise cancelling) are in the checklist at the last step of Headphones mode.

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