Close votes on a question expire after a period of time. How long is this period? Also, is there any way of telling how many close votes a question has garnered over time? This would include those votes which have expired.
I suppose the same question applies to delete and reopen votes as well.
Votes expire after four days, with provisos. It's explained on the voting privilege page.
An SEDE query like this...
select PostId as [Post Link],count(Id) from Votes
where PostId > 100000
and VoteTypeId = 6
group by PostId
having count(Id)>5;
...will find recent posts with more than five close votes. This could happen if a post is closed and re-opened and then closed again; or if close votes have aged and been replaced.
There aren't any questions with more than five close votes. Consequently it's not possible to find the total number of close votes including expired votes.
That said, there must be an internal record of total votes, because it's not possible to vote to close a re-opened question where you voted to close the first time round. But it doesn't look like that data is made available.
