As I mentioned in this thread, I am buying a Nokia N900 sometime in November, which is about to end. Actually, within the week, I hopefully be able to have enough money to buy this mobile computer. But as the title of this thread says, I am buying a 2nd hand Nokia N900. I want to ask what are the things to check for a 2nd hand Nokia N900 before really calling the deal and paying the 2nd hand device? Like would the sliding of the keyboard should be too loose? Or will faded keyboard or pressing of keyboard should be crisp? And stuff like what are the more important things to consider?

Thank you in advance

PS: I plan to buy another or even two when time and money allows it - hopefully