Sometime I'm in situations where I'm not 100% sure of my answer:
Let's say a user asks for the best lib to do X. I know that the lib A is great because I've heard people telling me that it is. Should I tell "use lib A" or "I've heard that lib A", or should I just leave people who actually used lib A answer (there might be none around) ?
A user asks about "how to do X". I do a search for that on google because I have a vague idea of how to do it but need more info to be more helpful. I end up finding something that looks really cool, but I have no clue if this really works. Should I tell the OP about it like "There is this solution A that looks great, but I haven't tested it." or should I just not answer the question if I have nothing better to provide ?
Sometime the OP is not specific enough in his question and people answer it by making some assumptions. Then the question can get edited and then the answer that was possibly correct might become totally wrong and get downvoted into oblivion. Should the user have waited for the OP to edit his answer (which might not happen and is hard to keep track of if you have no anwsered to the question in the first place)?
There is no perfect answer for all this, but I'd like to see you guys' opinion and how other SO users behave.
Personally, I try to avoid guessing or making assumptions. If I do, it is because I think it might be a good pointer for the OP, but then I always state in my answer that I'm not 100% sure that my answer is correct and that it requires some reading up.