Short answer: Run nine checks before you pay — IMEI status, battery health, display, cameras, Face ID or fingerprint, ports and buttons, network and Wi-Fi, activation lock, and the paperwork. Each takes under a minute. A seller who resists any of them is telling you something.
This checklist works whether you are buying from a brand, a marketplace listing, or a shop in a phone market. Run it in order — the early checks are the ones that end a deal fastest.
1. Verify the IMEI before anything else
Dial *#06#, then send an SMS reading KYM <15-digit IMEI> to 14422. If it returns blacklisted, duplicate, or already in use, the conversation is over. Also confirm the on-screen IMEI matches the one printed on the box.
Full walkthrough: how to run an IMEI check in India.
2. Check battery health, and demand a number
On iPhone: Settings → Battery → Battery Health & Charging. Read Maximum Capacity. On iPhone 15 and later, also check cycle count under Settings → General → About.
If the seller says “above 80%” rather than giving you a figure, assume the worst end of that range. A missing Battery Health section usually means a non-genuine battery has been fitted. See what each battery percentage actually means.
3. Inspect the display properly
Open a plain white image full screen, then a plain black one. White exposes dead pixels, yellowing and patchy backlight. Black exposes light bleed and burn-in on OLED panels.
Then drag an icon slowly into all four corners and along the edges. Touch dead zones cluster at the edges and are easy to miss if you only tap the middle. Look at the display from an angle too — a replaced non-genuine screen often shows a colour shift or sits fractionally proud of the frame.
4. Test every camera
Front, wide, ultra-wide and telephoto if fitted. Shoot a photo with each, then switch to video and back. Watch for dust specks inside the lens, a hazy or milky look, and autofocus that hunts. Shake the phone gently near your ear — a faint rattle can mean a failed optical stabilisation module.
Also record a short video with sound and play it back to check the microphones.
5. Confirm biometrics work
Face ID and fingerprint sensors are among the most expensive things to repair, and on iPhones they cannot be transplanted from another device. Ask the seller to remove their existing face or fingerprint and enrol yours on the spot. If Face ID cannot be set up, or the option is greyed out, the module has been damaged or replaced.
6. Work through ports, buttons and speakers
Plug in a charger and confirm it charges. Test wireless charging if supported. Press every physical button — volume, power, the mute switch or Action button. Play music through the loudspeaker at full volume listening for crackle, then make a call to test the earpiece.
Look into the charging port with a torch. Lint is normal. Green or white corrosion is water damage.
7. Test network, Wi-Fi and Bluetooth
Put your own SIM in and make an actual call. Confirm mobile data works, not just signal bars. Connect to Wi-Fi and load a page. Pair a Bluetooth device.
On a dual-SIM handset, test both slots. A faulty second slot is a common and easily hidden defect.
8. Check for activation lock
This is the one that turns a phone into a paperweight after you get home.
On iPhone, go to Settings → General → Reset and confirm the device can be erased without asking for someone else's Apple ID password. Better still, have the seller fully erase it in front of you and set it up as new. If Find My iPhone is still linked to their account, you cannot use the phone — and no repair shop can fix that. On Android, the equivalent is a Google FRP lock.
Never accept “I'll remove it later.”
9. Get the paperwork
Ask for a GST invoice in your name, written warranty terms stating who honours them and for how long, and a stated return window. A GST invoice is what makes the purchase legally yours and is usually required for any future warranty or insurance claim.
No invoice means no recourse. That is the whole point of the document.
The quick version
| # | Check | Deal-breaker if |
|---|---|---|
| 1 | IMEI status | Blacklisted, duplicate, mismatched |
| 2 | Battery health | Below 85%, or reading hidden |
| 3 | Display | Dead pixels, touch dead zones, burn-in |
| 4 | Cameras | Dust inside lens, focus hunting |
| 5 | Face ID / fingerprint | Cannot be enrolled |
| 6 | Ports, buttons, speakers | Corrosion, crackle, dead button |
| 7 | Network and Wi-Fi | Call fails, second SIM slot dead |
| 8 | Activation lock | Still linked to seller's account |
| 9 | Paperwork | No GST invoice, no written warranty |
What changes when a brand does this for you
This checklist is nine checks performed once, by you, in a shop, under time pressure, without diagnostic equipment. It catches the obvious failures and misses the ones that surface in month four.
A real renewal process runs over 300 quality checks on every device, on calibrated equipment, with degraded components replaced rather than noted. That is why every Premium Renewed iPhone ships at 100% battery health with an 18-month warranty — and why the checklist above becomes something you can run for reassurance rather than protection.
More on the difference: refurbished vs renewed vs second-hand and is a renewed iPhone worth it in India.
Frequently asked questions
How do I know if a refurbished phone is genuine?
Verify the IMEI against the government's Sanchar Saathi database, confirm battery health in Settings, test the display, cameras and biometrics, check the device is not activation locked, and insist on a GST invoice with written warranty terms.
What is the most common problem with refurbished phones?
A degraded battery that was never replaced. It is invisible on inspection day and becomes obvious a few months later, which is why battery health should be a stated number rather than a range.
Can a seller fake battery health?
Some tools reset the reported figure without changing the physical battery. Read capacity alongside cycle count — 100% capacity with several hundred cycles indicates a reset, not a replacement.
What is activation lock and why does it matter?
Find My iPhone ties the device to the previous owner's Apple ID. If it is still active, the phone cannot be set up or used by you, and no repair shop can remove it. Always have the seller erase the device in front of you.
Do I need a GST invoice when buying a refurbished phone?
Yes. It establishes legal ownership and is normally required for warranty or insurance claims. A seller who cannot issue one is not operating as a registered business.
