Buying second hand mobile might be risky as there wont be always a warranty or gurantee for that product but for any reason if you want to buy a second handle mobile, below are some points for you to remember :
) Before buying mobile check properly all of its parts whether its damage or not and functions working or not.
) If mobile is in good condition and you satisfied with it then check whether the seller is providing its bill and warranty card or no , if not then it might be theft mobile too so always go for mobile where you are getting its bill.
) Important functions to check before purchasing second hand mobile - camera , sound , mic, battery ( if not inbuilt) , body parts , screen , inbuilt memory .
)Purchase second hand mobile from shop because they will provide you bill of their shop and that will be a proof of purchasing .
Hope my tips was helpful for you . Thank you