Programming

The "correctness" of my code would probably the greatest single difference I've noticed in my own habits.

For example, I've become very strict with myself about using type hints and relying on appeasing type checkers and such. The way I structure my projects has changed, where I separate functionality from data to a larger degree, mimicking struct and impl where it makes sense to do so. I've pretty much stopped using dict, and rely on dataclasses instead when writing Python. I've given up on forcing everything to be OOP (even C#), which has made my code easier to read and maintain. There are probably other things as well, though I can't list them at the top of my head.

Some of it is probably just good practice, a result of having matured after being exposed to new languages. Some of it probably wouldn't be considered pythonic or idiomatic, but I'm not sure I care anymore. My code is more reliable (and often faster), and that's what matter in the end.