Writing simple code
My biggest beef with SOLID is that more so than the Ten Commandments, it's hardly actionable.
As a competition to that, the thesis is simple code itself will keep a code base highly maintainable.
Which leads to the problem of trying to define simplicity. I first tried doing that by formulating simplicity as the lack of complexity. But that led nowhere. Even if it's true it's hardly usable.
After some more thinking I arrived a definition I'm fairly satisfied with:
Simple code is a block of code that is self-explanatory within one view.
If you try to code in such a way that achieve this quality, I submit that most of SOLID is made obsolete.
It's a not a fully-formed idea yet; the attack surface to that statement is wide and vast. It is asking for long think-piece to examine to implications that follow.