I maintain some software for around 8 years now. And I just can tell from that: Organize your code and rewrite if it has some quality. The software I have, works but is terrible hard to extend and the really realyl big problem. I do have to add this extensions over and over again. At least if it’a about order, I’ have 4 different areas which nearly are the same to change. That makes it terrible and you can bet, I’ll oversee one area nerly always.
Be very carefula bout redundancy, but don’t get folled and think it’s always bad, but if it’s in more then three places, you are in deep trouble.
Yes quality matters and it’s worth it. It’s worth your time and it will hamper the further development if you don not care about it deeply.