When's the latest you can return to wow to get the full effect of the content? Before the next patch or before the next expansion?
Let me rephrase: I know blizzard removes content as they progress things, so if you weren't playing at a particular point there are somethings you can never experience, - i know you will never get a full expansion's story or experience if you didn't play while it was up, but I don't remember if they start removing some content as early as the next patch or if it all stays there till the next expansion.