In my experience maintaining things for even longer than that, if your code is verbose you are way more likely to make a mistake many years later because you don't remember all of the rules required to correctly edit or generate new code in the same form. You are much better off compressing that code using domain-specific abstractions that force all development to follow every mental model you ascribe to the code, even if it means you have to load more mental state and it takes you a bit longer to "back up to speed" in the code you haven't edited in a while, as it helps guarantee you actually load the correct state.

It depends on the specifics. I think a correct AI should look at the relevant context and give code with matching verbosity.