Old posts - should I add to them or create a new post?
Generally you should add your experience to the existing posts rather than having discussion about the same topic spread across multiple posts.
Even though some information becomes outdated, the changes that happen over the years add to the usefulness of the discussion and it is easier for readers to view a single discussion on a topic rather than needing to find all of the different posts about it.
Any responses that are out of date and no longer provide a correct answer can be downvoted so that they appear lower in the discussion. It's also helpful to reply to them directly with an update saying that the situation has changed.
You can then add and/or upvote responses that are correct for the current laws etc.
We try to keep the popular posts updated through the use of moderator comments as the first reply to each post. We often summarise any changes that have happened over the years to help avoid confusion about what the correct answers are.
Please feel free to ask further questions about this below so we can decide how older posts need to be updated to remain relevant!