...revived threads.
I am so tired of skimming threads thinking "this sounds familiar", and then realising that the bulk of the conversation took place months (or even years) ago. If there is a gap of more than a month between the final and penultimate post, then it needs a warning. Something like "choccy, you've already wasted hours 10 minutes of your dwindling life-span reading this, so don't make the same mistake all over again"
If someone is coming back to give an update, then I feel the best way is to start a new thread, and show the old one as a link.