Buying a used smartphone without bad surprises

A smartphone loses 30 to 40% of its value in its first year while losing almost none of its real-world ability. That makes the second-hand market one of the best deals in tech: a model two generations old sells for 40 to 55% of its launch price, still receives updates and will comfortably last another three years. Provided, that is, you know how to check what you are buying.

The market has its traps — worn batteries, blacklisted IMEIs, accounts still locked to a stranger, outright fakes — but none of them survives a methodical check: each one can be detected in under two minutes, on the spot, with the right steps. This guide walks through the five essential checks, the field tests that complete them, the right setting for a hand-to-hand sale, and price benchmarks generation by generation.

The five checks, in order

Run them every time, with the device switched on and in your hands, before any talk of money:

1. The battery. Settings, then Battery, then Health. Insist on 85% capacity or more; below 80%, a replacement costs €60 to €90 — deduct it from the price, figure in hand.
2. The IMEI. Dial *#06# and run the number through a checking service. A blacklisted IMEI means a stolen or unpaid device: carriers will eventually block it.
3. The accounts. iCloud or the Google account must be signed out in front of you, not "tonight when I get home". An active activation lock makes the phone permanently unusable.
4. Proof of purchase. The original invoice or receipt: it establishes ownership, the device's true age and the end of warranty.
5. Screen and touch. Display a white page to spot dead pixels and stains, then drag an icon across the entire surface of the screen.

Two more minutes of field tests

The five checks remove the big risks; two minutes of field tests remove the last doubts. Make a real call — microphone, speaker and reception reveal themselves in ten seconds of conversation. Take a photo with each camera, check the focus, film three seconds of video. Plug in the seller's charger, switch on Wi-Fi and Bluetooth.

Facing a "refurbished" device, ask two questions: refurbished by whom, and with what warranty? A professional refurbishment comes with an invoice and a written warranty of six to twelve months. Without both, you are buying an ordinary used phone that has been cleaned — and you should pay for it as such.

Where to meet, how to protect yourself

Daytime, in a public place with network coverage: a café, a station hall, a shopping centre. You want people around and a connection to run the checks, call included. Refuse the script of the parcel "shipped from abroad against a deposit": it is the fraudsters' most profitable routine, catalogued in our guide to spotting classified-ad scams. And keep the whole conversation inside the platform's messaging: it timestamps every exchange, which carries real weight in a dispute or a report.

The right price, generation by generation

Smartphone depreciation is predictable, which makes the fair price easy to establish: browse the high-tech category and note a dozen listings of the same model, at equal storage capacity.

• This year's model: 70 to 80% of new — rarely a good deal, depreciation has not done its work yet.
• Two generations old: 40 to 55% of new — the best ratio of price to remaining lifespan.
• Three generations and older: under 35% of new — first check how long the software updates will keep coming.

A recent model listed far below these ranges always has a reason — and rarely a good one. Conversely, a price slightly above them can be negotiated: a battery under 85%, missing accessories and micro-scratches are all arguments you can put a number on, to be raised calmly as our guide to negotiating without alienating the seller explains.

Pay protected, confirm, enjoy

The last link is the payment. Protected payment holds the funds until you confirm reception — the seller only gets paid once the device is in your hands and the checks are done, and a dispute can be opened if the description does not match; the protected payment walkthrough details every step. A seller who refuses this framework without a valid reason is doing you a favour: move on to the next one. There is no shortage of good deals — start your search and run the method.