First of all some of important things you must need to check whether it does not have scratches and dents on the phone.
The physical outer part can lead to further internal defects of phone.
So, firstly I will suggest to buy a phone with minimum amount of scratches or dents in the outer physical part.
Then another important part is display, press the touchscreen of the smartphone hardly, if it is pressing then there is a most chance that you have a phone in your hand with replaced duplicate display.
This system is the best and anyone of you can get it on Tecgram.com.
Just follow the steps given below-
Enable the developer options by tapping the ‘build number’ more than one times.
Then you have to go developer options and enable the ‘Pointer location’.
You should get an overlay on the top of your screen. So, touch the screen at multiple locations and you can observe ‘PRS’ value changing.
Actually PRS value represents pressure you are applying on the screen as well.
For a normal click, the PRS value should must be from 0.1 to 0.25 and for the long press, it should must be between 0.25 to 0.5.
If any discrepancies is available, then don’t take suddenly decision of buying the phone till you get it tested from service center.
Talking about phone sensors and battery and camera and calling features, anyone of you will get many applications, which apps are able to detect the sensors and phone’s battery life as well. In some cases during long time using of phone, the phone loose the battery life and the sensor capabilities.
So by sensor testing app and battery life app, anyone can detect the battery life and the sensors working capacity as well.
Also there are lots of apps available in the store for free to check camera and calling features of a old phone through software basis.
One other most necessery part is to check the hardware part properly. The hardware information apps is the best for it.
You can get this app in app store within you can get all the hardware information of the device.
The check warranty option in company website, just press and enter IMEI number of the phone and check the warranty status. If you find warranty period is not the consistent with bill, so then do not proceed for the transaction of buying that phone.
So, my final advise will be that all of you should keep those upper important siggestions on mind while purchasing a second hand smart phone device. Thank You.