Allow me to change my vote if I discover an answer is wrong after I upvote it
A few times I see an answer that upon reading seems to be exactly what I want -- the perfect solution to a problem. I think wonderful, my problem's solved and upvote it. A half-hour/hour/day later after I've tried implementing their solution, I come across a roadblock -- their solution fundamentally won't work and could never work; e.g., they tried to do some sort of action not allowed by the web framework.
Not only did their solution not help; it wasted a lot of my time implementing something that could never work. And now the next person who comes along will see their solution and try to implement it and will see that it's upvoted. Maybe I'll write a comment; but maybe they'll miss it or decide they need to try it themselves (hey it has a few upvotes -- it must have worked for some people, right?).
Now, if I have enough reputation I can trivially edit their question and then be allowed to change my vote; but to me that seems like cheating the system in an unintended way.
I think a better method would be to unlock the votes if you leave a comment. Or have the vote message say, your vote is locked until you leave a comment saying "Changing vote" followed by a reason (or had -1/+1 that is opposite your original vote; then you are allowed to change your vote to that).
I know this is similar to other requests:
but I think that having vote locking is a good feature; just maybe relax it following a user leaving a comment in a way similar to how its relaxed after the answer is edited.
Otherwise, I think I'm going to have to seriously cut back on voting.
Update (9 years later by a different person):
The feature request that suggests specific changes should not be considered as a duplicate of discussion about similar issue that even doesn’t have the same proposal.
Comments are a part of content (even if they considered as second-class citizens). If any content is changed (similar to current post edits) since the user’s original vote, votes should be allowed to be changed as well.
The system should reflect the current opinion of users, support dynamic update of users views and do not encourage cheating by doing minor editing.