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Checking a used iPhone before you buy it: a 5-minute bench routine
Identity first
Confirm the model identifier matches the phone in your hand, and that the serial, IMEI and board identity agree with each other. A handset assembled from several donors — a "frankenphone" — usually fails this first check, before anything else is even tested.
Then parts
Display, battery, cameras and the biometric module are paired to the board on modern iPhones. Mismatches do not always produce an on-screen warning, but they are visible in the pairing data. A swapped display is not fraud; an undisclosed swapped display is.
Then the battery's history
Cycle count, capacity, internal resistance, deepest discharge, thermal events. Together these say whether the cell has months or years left — which is what actually determines whether the phone is worth the price.
Then the phone's past
- Unexpected restarts and sudden shutdowns in the recent log.
- Kernel panics, and whether one token repeats.
- Indications of liquid ingress.
- Whether the storage is reporting corrected errors.
Give the buyer proof, not your word. A report the buyer can verify themselves turns a haggling session into a transaction. It is also the cheapest protection you have against a return claim two weeks later.
What "no faults found" is worth
A clean report is worth as much as a bad one. It is the difference between "I think it's fine" and a document showing 23 subsystems checked, the battery's own records, and a verification link the buyer can open on their phone while standing in front of you.
Read it from the phone instead of guessing
PhoneVitals pulls every number in this article off the device itself over USB — the gauge records, the panic logs, the pairing checks — and prints them in a report your customer can verify by QR code. The first scan on your computer is free.
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