How to buy a used iPhone?

HOW TO BUY A USED IPHONE Check Verify the IMEI Number Activation Lock Verify DEVICE'S dobile SERIAL NO Your Tech AJiser Make sure the device is IMEI ESN and IMEI cleaned Reset the To see if there's water damage, Phone check the SIM card tray and the headphone jack Make sure it has no dents and minimum number of scratches bileSiri Your Tech Adviser Make sure that the device is Carrier 1 unlocked and works on all carriers Check camera, Auto focUs should work fine. make a video of at least 10 seconds if mobile turns off with in 10 seconds it means the CPU is damaged otherwise it's all good Check all the buttons ( Home, Volume rocker, power) are not so hard and work softly Make Sure that the 3D touch works properly on iPhone 6S and Check the flo of touch, it should work fluidly latest models Record your voice to check microphone and the speaker of the phone, it's good if you record you whistle because it's frequency is quite different than that of normal human voice. While testing headphones revolve the pin constantly to Make Sure the GPS Make a call in a works fine ensure there is no strong signaled damages inside the ribbons zone and check the quality of Sound, if it lags continuously it means the IC is damaged. Make Sure the WiFi and Your Tech dviser Bluetooth Work fine Check the transfer of data via Airdrop and physically via USB cable To check the drainage of battery; set the screen brightness to max, turn on wifi, turn on Bluetooth, insert a sim card and play a HD video online or offline. If your battery drops rapidly just in minutes it shows that the battery is weak. For benchmarking test, try Antutu benchmark, Geekbench3, 3D Mark GPU test and Sunspider (Java script browsing test). REFERNCES: http://www.cnet.com/how-to/4-tips-for-buying-a-used-iphone/ http://www.iphonehacks.com/2014/03/tips-buy-Used-iphone.html http://www.macworld.com/article/1167810/smartphones/what-to-watch-for-whenbuying-a-used -iphone.html http://www.guidingtech.com/38237/buying-used-iphone/ https://www.youtube.com/watch?v=afGtZSm-Sw4 https://www.youtube.com/watch?v=C7Z8M4CRHGK