I have no problem with bumping old threads as long as there's something worthwhile to add to the discussion. There's no point in welcoming someone to the boards who registered over a month ago (as an example).
Also, nobody likes double posts unless the thread has completely disappeared and you're bringing it back up due to an important update. If you find things to change in a post you made today, or anytime recent, (not speaking to anyone specific), use the edit (
) function on the right of your posts.