[arcwhite]

I've seen code persist a long time because it is unmaintainable gloop that takes forever to understand and nobody is brave enough to rebuild it.

So no, I don't think persistence-through-time is a good metric. Probably better to look at cyclomatic complexity, and maybe for a given code path or module or class hierarchy, how many calls it makes within itself vs to things outside the hierarchy - some measure of how many files you need to jump between to understand it

[refactor_master]

I second the persistence. Some of the most persistent code we own is because it’s untested and poorly written, but managed to become critical infrastructure early on. Most new tests are best-effort black box tests and guesswork, since the creators have left a long time ago.

Of course, feeding the code to an LLM makes it really go to town. And break every test in the process. Then you start babying it to do smaller and smaller changes, but at that point it’s faster to just do it manually.