I do much the same as Strongers. If a pub has had a major refurbishment, or there's a significant change since my previous visit, then I will post a new review. I used to edit/add to my previous review, with a statement something like "the following from Apr 2010", but now I tend to post a new review as I think it makes the timeline of comments a bit clearer. However, I accept that there is also merit in editing postings as it then displays all the information at a current date, at the top of the pile as it were. I don't think that there is a right or wrong way of doing it.