I have learned to do searches before I post a thread just to make sure a topic has not been covered before but I've noticed some of the topics are very old. Is it best to start a new thread on a topic which has already been covered in the past or is it best to revive the old one? I'm never quite sure what I should do.
In my opinion, if you have a new angle to add then to start a new thread, but if it's a general query then I would continue with the old thread. For example if people didn't there would be (and are in some cases) multiple threads with the same headers and information. It gets confusing, then as to which to answer and what is up to date.
I suggest to revive the old topic because it will help people to see how the topic has changed in the recent times and it will act as a update. Like @Theo said, if there are two threads with the same topic in it, then it will be confusing for the users.
I don't think your points will match exactly or perfectly as the one conveyed in the old topic. You'd have to phrase your post not appear same but portray your angle of thought on the topic even though it resembles the old somehow. This may qualify as an update to the old.
I ask because some forums discourage reviving old threads because many of the people who posted would be gone and a new thread with new opinions seems preferable. I'm talking about threads that were started 2 or 3 years ago. If a thread was started this year or the end of last year I would probably post on that.