Have you ever been reading a comic and tried to figure out what the heck is going on. This will happen often to me as I’m reading a book and I see a character that is flying when for the last four months in that character’s book their ability to fly had been destroyed somehow. Aquaman shows up in a book and he looks more like Orin, Spider-Man is still in his black costume after abandoning it in his own comic after awhile.
Well almost all of these problems can be resolved by checking sales figures for comics. It has been determined that if the sales of a comic are below 20,000 books a month, then there is no impact to continuity. As a writer you are free to ignore it and move on.
There is even a codicil to that rule. If your books are some of the highest selling books on the market than you are free to ignore almost any continuity and pick and choose at your leisure. This explained why Geoff Johns, Brian Bendis and other top selling writers are able to work as fast as they do. Research is cut down immensely if you can just go on memory and make stuff up as you go.
In fact I have started to add my own corollary to the continuity rule. My rule is that if I never read it, it never happened. It doesn’t always work, but at least it allows me to skip over inane elements in certain stories at different times.