When and how should I down-vote old posts? [duplicate]

Question

Possible Duplicate:
Why do you cast downvotes on answers?

I've been on SO for only a few months. I've been doing a lot of browsing, playing catch-up with the huge body of knowledge that's accumulated here. Naturally I've been voting here and there along the way. I know there's already been this discussion on upvoting old solutions. But what's proper etiquette for downvoting old solutions that I come across (old being anywhere from a few months to years ago)?

Now that I think about it, there are a few separate scenarios:

1. I'm the first to discover something wrong with an answer. It seems like here I should downvote and post a comment, even if the post is years old?

2. The answer's been downvoted once or twice, but not seemingly unanimously. Maybe there's evidence of disagreement in the comments. Should I also downvote it, to show my years-late solidarity with its critics?

3. The answer was overwhelmingly downvoted. Given I agree with the downvotes, should I also get my kicks in, as long as I'm there?

For each of these situations, would downvoting be helpful to the site, or just unnecessary/amateurish?

Answer 1

1. Yes you can down vote. Yes you should comment. And if you're able to, edit or suggest an edit to an exists answer. If they are no longer relevant, feel free to add a new answer! Improving the quality of the Stack Exchange sites is always a good thing!

2. You can down vote if you like. You can upvote if you like. When things are ambiguous, often more research is necessary. Feel free to post comments to old questions asking for clarification. If the question is of personal interest, you can also add a bounty to attract more attention.

3. For this one, as a matter of personal opinion, I wouldn't beat a dead horse. If the answer can be improved feel free to do so -- edit / suggest an edit. If it's 'not-an-answer' feel free to flag it and raise it to the attention of a moderator.

In all situations, please abide by the faq -- When should I vote down

Answer 2

First off... If you don't think an answer is helpful down-vote it. This holds regardless of age. You're voting to communicate with other readers, not so much with the author (who may well be long gone even if you're viewing it five minutes after it was posted).

It seems like here I should downvote and post a comment, even if the post is years old?

Yes! In fact, you may even want to make or suggest an edit that corrects the problem, if you can come up with one. There are no hard and fast rules for this of course; if another answer exists which is correct, you can simply up-vote that, and if the corrections are too extensive you might as well just post an answer of your own... But don't hesitate to try - a comment pointing out a problem, while helpful, doesn't go nearly as far as simply fixing the problem completely.

Should I also downvote it, to show my years-late solidarity with its critics?

Sure! The folks who disagree with the criticism certainly aren't withholding their votes. If you do, you're doing a disservice to the less experienced readers who follow you...

Given I agree with the downvotes, should I also get my kicks in, as long as I'm there?

Eh, why not. The author could presumably have fixed or deleted it if he'd wanted to; maybe one more down-vote will finally clue him in to his error... Or at least convince him to make a more compelling argument in favor of his solution. That said, if the answer already sorts last, and is unlikely to ever rise in position, this is less crucial; if you're low on votes that day, or low on rep, you might skip it without guilt - readers will know well enough not to try it.