I believe the greatest value in my code is that it can be extended and adapted over time as the problem it tackles and the scope it covers evolve. To support this I do my best to ensure that my code is well written and easy to understand and follow when I come back to it weeks, months or years later & I think hard about making life easy for other developers who might have to work with my code in future.
Legacy code matters too. Sometimes its hard to write tests for and changing it can often be fraught with risk. I always approach legacy code with care and I always strive to leave it better than I found it.
With these tenets in mind I never stop learning and I never stop trying to get better at my craft.