The 5‑minute shop checklist
Do these in order. If step 1 fails, you're done — move to the next shop.
1. Deal‑breakers first (2 min)
- Settings → top of the screen must show “Sign in to your iPhone”. If a name/Apple ID is there, ask the seller to sign out and erase in front of you.
- Dial *#06# and note the IMEI. It must match the SIM tray and Settings → General → About. Check it on an IMEI blacklist checker.
- Set up Face ID (or Touch ID). If it says “unable to activate”, walk away — it can't be repaired cheaply.
2. Battery
- Settings → Battery → Battery Health & Charging. 85%+ is good, under 80% needs a replacement soon.
- Cycle count: Settings → General → About (iPhone 15 and newer). Under 300 is excellent; over 800 is heavy use.
- If it says “Unknown Part” or “Service”, the battery was swapped with a non‑Apple one.
3. Replaced parts
- Settings → General → About → Parts and Service History (iOS 17.4+). Shows if display, battery or camera were replaced.
- Open Control Center and long‑press brightness: missing True Tone means the screen is usually not original.
4. Hardware test
- Show a full white and full black image — look for dead pixels, yellow tint, burn‑in.
- Open the camera: test every lens, zoom, flash, front camera and a short video.
- Record a voice memo and play it back (mic + speaker). Make a call with your SIM.
- Press every button, flip the silent switch / Action button, plug in a charger.
- Connect to Wi‑Fi and Bluetooth. Lay the phone flat to check for bends or a lifting screen (battery swelling).
5. Before you pay
- Ask for a written warranty (even 7 days) and a receipt with the IMEI on it.
- Compare its score here with the other phones you've seen — don't buy the first one under pressure.
- Take photos of the phone and its Battery Health screen for your records.