This is an important point I like to mention to people. Thinking back to old code you wrote and how you would choose to do it better than you originally did it a sign of growth, and if that stops happening after a certain point, it's a sign you've stopped growing. Given that the best programmers in the world still don't write perfectly bug-free code, I don't have any illusions that there will always be plenty of room for me to continue improving as a programmer, so I consider having those thoughts to be an unequivocally good thing. I'd honestly be a bit wary of anyone who didn't think they needed to learn or grow any more as a programmer!