I think it is time * (votes+comments).

In practice, if it gets any real amount of votes or comments, you have to wait a year to repost. If it doesn't get any attention, it can be reposted quickly (though I think it should be a day later).

It depends. I tried posting a few links I came across over the past few days, and it just showed me dups but they were from days or weeks or sometimes months ago.

Not sure why this comment is downvoted. Yes, I got redirected for a dupe earlier today for something posted 7 months ago. And even though the content substantially changed, it can’t be posted again.

I seem to remember getting that and having the option to post it again. Maybe it’s a karma related thing.

I thought that number was significantly more than 9.

It seems like, if the link is the same, submitting a dupe should just raise the original.