Used Phone Buying Checklist: What to Verify Before You Pay

A used phone is usually the cheapest way to get onto a low-cost plan, and it is also the easiest place to lose a few hundred dollars. Nearly every bad outcome comes from a check that takes two minutes and gets skipped because the seller seems fine. Work through this list in order — the early items are the ones that make a phone worthless rather than merely disappointing.

1. IMEI status — do this first

Ask the seller for the IMEI before you meet, and dial *#06# on the device itself when you do meet to confirm it matches. A device reported lost or stolen is placed on a shared blocklist, and a blocklisted phone cannot be activated on any major US network. No unlocking service can fix that, and there is no refund path once cash has changed hands.

• Confirm the IMEI on the device matches the one you were quoted.
• Check the IMEI against a reputable status checker before paying.
• Walk away from any seller who will not provide an IMEI in advance.

2. Activation lock and account sign-out

An iPhone still signed into the previous owner's Apple Account, or an Android device still tied to a Google account, is locked to that person after a factory reset. The fix requires the original owner, so it must be resolved before payment, not after. Insist on watching a full erase and setup: the phone should reach the 'Hello' or initial setup screen and let you get to the home screen without being asked for someone else's credentials.

3. Carrier lock

A carrier-locked phone only accepts SIMs from the provider that sold it. On iPhone this is visible under Settings, General, About, at the Carrier Lock line — 'No SIM restrictions' is what you want. On Android the wording varies by manufacturer, so the reliable test is inserting a SIM from a different provider and confirming it registers. Unlocking is often possible later, but it is leverage on price today and it is not always available.

4. Outstanding financing

A phone still on an installment plan can be blocklisted later if the original owner stops paying, even though it works perfectly the day you buy it. This is the most common way a legitimate-looking purchase fails weeks after the fact. Ask directly whether the device is paid off, and prefer sellers who can show it. An IMEI check that returns a 'financed' or 'unpaid balance' flag is a reason to walk.

5. Battery health

On iPhone, Settings, Battery, Battery Health & Charging shows maximum capacity as a percentage. On Android, capacity reporting depends on the manufacturer; where it is not exposed, treat age and charge-cycle habits as a proxy. A replacement battery is a known, bounded cost — factor it into the price rather than treating it as a dealbreaker, but never pay a premium price for a heavily degraded battery.

6. Network band compatibility

The same phone model is often sold in several regional variants with different radio bands. An international variant may work but lose specific 5G bands, which shows up later as worse indoor coverage rather than an obvious failure. Check the exact model number — on iPhone it is the A-number in Settings, General, About — against the compatibility checker for the network you plan to use.

7. Physical and functional inspection

• Screen: look for burn-in on an all-white image and dead pixels on an all-black one.
• Touch: swipe every edge and corner; digitizer damage often hides at the margins.
• Cameras: shoot with each lens, front and back, and check for haze or a rattling stabilizer.
• Audio: play music through the speaker, make a call, test the microphone with a voice memo.
• Ports and charging: charge wired and, if supported, wirelessly.
• Water indicators and frame: separation around the screen edge suggests a swollen battery or a past repair.
• Face or fingerprint unlock: non-functional biometrics often indicate a third-party screen repair.

8. Where you buy changes your recourse

If you are buying locally with cash, meet somewhere with reliable signal so you can actually complete the network tests, and treat any pressure to hurry as a reason to stop.

Next steps after you buy

Confirm the lock status once more on your own account, verify compatibility with your intended provider, and only then plan the number transfer. If the phone turns out to be carrier-locked, resolve that before starting any transfer.