I have a mint condition 16GB 1st generation iPad for sale. Since it cannot be upgraded to iOS6, I would like some advice regarding how long its useful life is likely to be. I don't want to mislead potential buyers nor sell something that will be dead in the water within the next year. I sold an iPhone 3GS last December and at that time I was satisfied that it would be suitable for at least a couple of years. For example, I have a potential buyer who wants an iPad for her son (I don't know how old he is because I haven't had an opportunity to ask). I want to be sure that he will be able to use it for a reasonable period of time.