What ever you decide to do it needs to be an arrangement that, at the end of the day, you can be happy with. i.e. if you decide to continue going the extra distance for this guy and he continues to be a prat then you've gone into it eyes wide open. I think you sound extremely nice and living out the principle that ideally we treat others as we'd like them to treat us. Unfortunately lots of people only want that to be a one-way street (with them as the sole benefactors!). It's a precendent you can use for other purchasers who decline the warranty offer - either insist on it or stick to your guns about not doing extra work if they come back. As long as you sold the item in working order I don't see how they can remotely come back whinging. Caveat emptor???
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