A merge can occur at a moment's notice. We usually allow some time to pass, though. I am not sure what signs you are expecting to see that a merger is likely to occur. (Other than the duplicate notice, that is, which is essentially saying just that.) When the merge occurs, it can be in either direction, not necessarily new into old. Not that it really matters — when all the answers are on the same page, who cares what that page's URL is. As to question titles, that's a red herring because a) these can be
edited, and b) they don't need to be edited, as they will point to the same page anyway. —
RegDwigнt ♦ 18 mins ago