When you don't have time to learn -- mob program.

To program a feature that's appropriate, functional, and secure, you need knowledge of the domain and customer, of the language and tools and platforms, of security and scaling. As a developer, you can learn all those things eventually.

If the need for software change is too urgent to give you time for learning, then bring all that knowledge into one room, in an ensemble of people. Code it together. As a bonus, everyone learns more about everything.

Why do we learn? in order to act. Ensemble programming says: get people with the knowledge together, in one collective focus, and skip to acting. Act (in a way conducive to learning), and learning will happen.