The only continuity that has or ever will matter is the story, aka whatever story the current writer is trying to tell with the character. Books the writer isn't writing don't have to be consistent with each other ie Superman in JL and Superman in his solo title need not share the same continuity. What happened in the book before the writer took over doesn't matter. Just as long as the continuity is consistent within that title and within that run it's all good. Now, when a writer can't keep the continuity he or she has established straight? That's just awful.