There’s an easy way to keep things simple: Either build on earlier stories without changing them (or change only the obscure stuff), or start over.
Retcons are like epicycles, the sort of secondary orbits that astronomers invented to explain discrepancies in planets’ motions when they thought the planets all had circular orbits and revolved around the Earth. The epicycles got more and more complicated until enough people noticed that you could get rid of most of them if you assumed the planets revolved around the Sun. Then they realized that you could get rid of the rest if you assumed the orbits were elliptical instead of circular.
If you *totally* reboot a series, like Wonder Woman after COIE or Legion of Super-Heroes after Zero Hour and again last year, things are simple. It’s just like launching the Justice League cartoon — it’s a totally separate continuity from the previous version, so contradictions aren’t a problem.
When you revise *parts* of history, things get complicated. Wonder Woman herself might have had a simple reboot, but the Justice League and Wonder Girl (Donna Troy) were still around, and their histories had to be revised. Donna has gone through *how* many origins since then? Origin-wise, she’s hardly recognizable. They actually did a better job with Power Girl by saying “Forget all the retcons, she really is the cousin of Earth-2’s Superman”
Sorry about the rant…