How long are user edits visible to the public?

Sorry. Maybe I’m not explaining it well.

Say, in a fit of passion, I write that John stinks. Next day I realize my indescression and go in to edit the post to remove the “stinks” bit. My question is, how long does the original text about John’s stinkiness stay around for people to go back and see.

If I delete the whole post then I think within 24 hrs it disappears. I’m just wondering if there is a similar threshold for previous versions of a post. Sorry if I wasn’t clear.