going to buy a new Iphone 4S very soon from Apple store, looking for tips

hi i am going to buy a new Iphone 4S from a local Apple retail very soon.

I am completely newbie to it. but I am a serious buyer I don't want to get something unhappy

I have been research on web and find out something I need to check about when I first get a brand new Iphone 4S from the staff,

I would llike to know if I've missed anything about that.

check IMEI
check the model part
check dead pixel
check whether any yellow line / splotches
check button responsivness
check camera by snapping a shot and using flash
check sound quality by making a test call
cosmetic - check whether any scratches or rough edge.

is there anything else? anything I've missed?

Thanks!