I had a boss call me a tumbleweed dev (when I was much younger). I would clean up bits, but this would mean the QA had to re-test code that was already tested and in production. I never forgot that term, and now if it an't broke, I don't touch it. (even if I don't like reading it)

that is both right and wrong. Right that they need to QA it, which is a cost. Depending on current ecconomics one they don't want to pay today. Wrong though because eventually they will need to pay it - when someone needs to spend the time to figure out what the weird code is doing (CS101 algorithms are not always obvious when not given a name even though simple once you realize what is happening).

Not cleaning things up as you go is why many projects have declared bankruptcy and done a billion dollar rewrite. We learn things over time, but if you don't apply the lessons you end up with really bad code.

OTOH, just changing everything all the time isn't right either. Find the correct balance so your code is constantly improving and as a result maintanable for centuries.