Precisely. The best measure is what you need to learn to scratch your itch. I like to call it just-in-time learning. A good place to look for where to improve

Precisely. The best measure is what you need to learn to scratch your itch. I like to call it just-in-time learning. A good place to look for where to improve is by reading your own code. Read stuff you wrote a week ago. Are you happy with it? What's wrong with it? Too verbose? Not legible enough? Poor perfomance? If you don't know exactly how to improve, try leaving your safety zone. Experiment with different languages or designs, see what they have to offer that your current toolbox is lacking.